Most drug users that know they are going to be tested, ESPECIALLY the milder drug users, will avoid the substance until the test has passed. I used to work at a place that employed mostly potheads, but they drug tested, and no one ever got fired over it. I know one person that was an idiot and smoked the day of the test and had to go to treatment over it, but that's beside the point. What I'm getting at is that people will still use. It's not going to do a lot to stop them.
All the while, Rick seems to be setting up things that will make him even more wealthy in the future. Again, I'd rather see sweeping cuts to the welfare system or some major changes like required volunteer hours (oxymoronic, I know) to get a little value for the money. At that point, I wouldn't really care as much if they smoked a bit on the side, because they're now doing something other than sitting at home watching Maury, while thinking about how they're going to get on the show.
Donaldson makes an awfully good point about food stamps. We have some friends that play the system (I know, right). They get more money in food stamps than they can use in a month. They eat far better than we do, and always have things like cases of Red Bull and lots of junkfood around the house, all payed for by the food stamps program. Anyone remember the commodities program? They give you a box of food that will allow you to make good meals and generally make ends meet. I know that's a dangerous step towards bread lines, but it makes more sense than taxpayers paying for 4 cases of Red Bull a month.