In an attempt to clamp down on underage drinking, Michigan lawmakers passed a keg tagging law in 2010, which required all kegs purchased in the state to be tagged (removal of the tag could lead to a hefty fine). According to MLive.com, Michigan has now repealed the law since it mostly just resulted in consumers substituting other forms of alcohol containers--cans, bottles, etc.--for kegs:
"The keg tagging policy one lawmaker calls 'a failed experiment' will be no more in Michigan. On Tuesday, Gov. Rick Snyder signed legislation to repeal a law passed in 2010 to put additional restrictions on keg sales in an attempt to curb excessive and underage drinking, particularly among college students.
Under that law, which took effect in 2011, any keg buyer had to sign a receipt that listed their name, address and phone number and show identification upon purchase. The law also imposed a $30 keg deposit -- which couldn't be claimed upon return unless the keg tag remained intact -- and made removing a keg tag a misdemeanor punishable by up to 93 days in jail and up to a $500 fine...
Many retailers noticed a quick drop in keg sales once the law took effect, but also noticed an uptick in sales of liquor, cases of beer and other alcohol that did not require registration or deposit.
Other issues, including the high price tag, difficulties keeping the tag on, monetary loss for unreturned kegs and little to show in terms of preventing underage drinking quickly drew critics from various industries..."
Read more here.