Yes. There will always be the bottom feeders that will try to squeak out a buck or two from the weak.
I think you're grasping at straws, my friend.
I understand that there are those out there who trade alcohol on the black market to minors, but their numbers are so few as to render them insignificant in the grand scheme of things. These people are analogous to the "pushers" you're fretting about under a drug decriminalization scenario.