yeah it would be very easy to abuse.

but they really don't care. The problem is to bad to control becuase they would have to imprison well over half of mexico. So they don't waste time with the users only the dealers. Cut the problem at the root.

what I think they might do is if they find someone with drugs they will just ask were they got it and let them go. But more than likely this is just going to Backfire into there faces but we will see.