They're just a brainstorm. The simplest and most effective would probably be measuring BMI for rewards. It could put some brakes on the obesity epidemic. Being paid to do nothing isn't exploitable, because there are no rules, but that doesn't necessary make it better, because there is no connection between effort and reward.

True, but some of them are easily automated. College credits, safe driving.

I think they were all just examples, so perhaps other examples that could be automated could be substituted.

Beyond that, probably less exploitable than the current welfare system (in America), and with less reward.