I don't know that Coors was ever illegal, but until sometime in the 80's, the company only distributed it west of the Mississippi.

This has been in the news here alot lately:

States Outlawing Synthetic Marijuana K2 'Spice'
Updated: Tuesday, 25 May 2010, 10:28 AM CDT
Published : Tuesday, 25 May 2010, 10:27 AM CDT

(CANVAS STAFF REPORTS) - Teens nationwide are getting high smoking a legally sold synthetic drug that acts like imitation marijuana but comes with some dangerous side effects.

Nearly a dozen states are banning or considering bans on "K2" – a packet of chemicals that turn herbs into synthetic marijuana, according to USA Today.

K2, also known as "Spice," "Mr. Smiley," "Genie," and "Zohai," is sold online, in convenience stores and in herbal or spiritual shops, and is usually marketed as incense, the newspaper reports.

Clemson University organic chemist John W. Huffman created the K2 compound in the mid-1990s to mimic the effects of cannabis on the brain .

Now produced in China and Korea, the herbs and spices concoction is sprayed with a synthetic compound chemically similar to THC, the psychoactive ingredient in marijuana. Users roll it up in joints or inhale it from pipes.

K2's key ingredients are banned in most of Europe, but have not been regulated in the United States.

Poison Centers nationwide have reported 352 cases of people sickened by the substance in 35 states, according USA Today. Patients who have smoked the faux dope have complained of hallucinations, paranoia, severe agitation, elevated heart rates, vomiting, seizures, and dangerously high blood pressure.

Toxicologists at three universities and two governmental agencies have launched a study into K2's potentially dangerous side effects.

Dr. Anthony Scalzo, a toxicologist at Saint Louis University, explained that these symptoms are not typical to those who use real weed. "They think they're going to mellow, and that's not what's happening," he told The Associated Press.

Meanwhile, lawmakers in Kansas, Kentucky, Alabama, Georgia, Missouri and Tennessee have voted to ban K2, while legislature Illinois, Louisiana, Michigan, New Jersey and New York are considering bills to outlaw the drug.

Source of article:
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Some interesting facts about margarine being illegal..
United States


As early as 1877, the first [You must be registered and logged in to see this link.]
states had passed laws to restrict the sale and labeling of margarine.
By the mid-1880s, the U.S. federal government had introduced a tax of
two cents per pound, and manufacturers needed an expensive license to
make or sell the product. Individual states began to require the clear
labeling of margarine. The color bans, drafted by the butter lobby,
began in the dairy states of [You must be registered and logged in to see this link.] and [You must be registered and logged in to see this link.].
In several states, legislatures enacted laws to require margarine
manufacturers to add pink colorings to make the product look
unpalatable,^{[You must be registered and logged in to see this link.]} but the Supreme Court struck down New Hampshire's law and overruled these measures.^{[[You must be registered and logged in to see this link.]]}
By the start of the 20th century, eight out of ten Americans could
not buy yellow margarine, and those that could had to pay a hefty tax on
it. [You must be registered and logged in to see this link.]
colored margarine became common, and manufacturers began to supply
food-coloring capsules so that the consumer could knead the yellow color
into margarine before serving it. Nevertheless, the regulations and
taxes had a significant effect: the 1902 restrictions on margarine
color, for example, cut annual U.S. consumption from 120 million to 48
million pounds (60,000 to 24,000 [You must be registered and logged in to see this link.]). However, by the end of the 1910s, it had become more popular than ever^{[[You must be registered and logged in to see this link.]]}.
With the coming of [You must be registered and logged in to see this link.],
margarine consumption increased enormously, even in unscathed regions
like the U.S. In the countries closest to the fighting, dairy products
became almost unobtainable and were strictly [You must be registered and logged in to see this link.]. The [You must be registered and logged in to see this link.], for example, depended on imported butter from Australia and [You must be registered and logged in to see this link.], and the risk of [You must be registered and logged in to see this link.] attack meant that little arrived.
The long-running [You must be registered and logged in to see this link.] battle between the margarine and dairy [You must be registered and logged in to see this link.] continued: In the U.S., the [You must be registered and logged in to see this link.] brought a renewed wave of pro-dairy legislation; the [You must be registered and logged in to see this link.],
a swing back to margarine. Post-war, the margarine lobby gained power
and, little by little, the main margarine restrictions were lifted, the
most recent states to do so being [You must be registered and logged in to see this link.] in 1963 and [You must be registered and logged in to see this link.] in 1967.^{[You must be registered and logged in to see this link.]}Lois Dowdle Cobb (1889-1987) of [You must be registered and logged in to see this link.], [You must be registered and logged in to see this link.], wife of the agricultural publisher [You must be registered and logged in to see this link.], led the move in the United States to lift the restrictions on margarine.^{[You must be registered and logged in to see this link.]}Some unenforced laws remain on the books.^{[You must be registered and logged in to see this link.][You must be registered and logged in to see this link.]}
There are people who actually remember when margarine was smuggled in cars across the borders because many couldn't get real butter for various reasons.

Coors beer.. Tater, you may be right on why people couldn't legally have it...

For much of its history, Coors beer was a regional product mostly confined to the American west by legal restrictions. This made it a novelty on the east coast, and visitors returning from visits to the western states often made a point of bringing back a case. This iconic status was reflected in pop culture: in 1977 the movie [You must be registered and logged in to see this link.] centered on an "illegal" shipment of Coors from [You must be registered and logged in to see this link.] to [You must be registered and logged in to see this link.]. [You must be registered and logged in to see this link.] great [You must be registered and logged in to see this link.] was such a big Coors fan that when he loaded up the team plane with multiple cases of Coors for the return trip to the East Coast, some of his teammates jokingly wondered if the plane would be able to successfully take off. The company finally established nationwide distribution in the U.S. in the early 1990s.
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Breezey, I did see that, but it doesn't site the reasons for the legalities involved, so I didn't give it much weight.
The only logical explanation I saw about it was that because Coors didn't use any preservatives, it had to be brewed, shipped, and stored cold, so distribution was limited to the ten western states closest to the brewery in Colorado. Some states did try to restrict or outlaw unpasteurized beer; I'm thinking that Wisconsin may have been one of them, since they were home to the second largest brewer, Miller beer.

I think you have a good point. It would only be logical to stick to an area you can deliver in without problems arising.