What stats are you using to say things are bad now?
What percentage of drug users do you think are taking advantage of the system and how does this address the reall issues of the people who are clean and abusing the system.
These seems to me to be a solution in search of a problem.
You don't think people are able to work, but aren't, and instead are collecting welfare? The system has been proven to be easy as hell to take advantage of. If you don't believe that it's happening en masse, then well, that's your problem. It's human nature. Some people have the drive to work and reap the benefits of said labor, while others will do anything, including jumping through legal hoops not to.
I don't need stats to show me that a lot of people drive drunk, don't pay child support, steal, rob, murder, or take advantage of welfare and disability to know that they exist, and that they are problems.
You can choose to live in a fairy tale world where everyone has a sense of civic responsibility if you like.