I would suggest that the drug testing also extend to the parents who get food stamps and other forms of govt assistance , such as Section 8 housing. Why? If you can afford to be doing drugs, you can easily afford to pay your way with regards to food and housing. Also, by doing the test as parents, you are showing your kid, by example, that the process is harmless and safe, and only has consequences if you are a user. If a kid sees his parent or parents refusing to take a test that the kid is expected to take, can we (and the kid) logically assume that the parents have something to hide, are on drugs and should not be receiving govt support and freebies?

My guess is that parents will say no, that drug testing is an infringement of some sort of rights, especially if they are users. For them, not clean legit food stamp users, that makes the food stamps as simply enablers for druggies. Any cash they earn goes for drugs, not food, and the stamps supplement their lifestyle. That is wrong. Why should I have a say? My tax dollars are paying for those food stamps, and that gives me, and the govt, the right to insist that our taxes are being spent wisely.
So, can we have free drug tests for both parents and kids with the denial of food stamps in the mix? Kids can't get food stamps, so only 'responsible' adults will face the challenge.