[Spoom]

I know if I was given $30,000 a year for free with the understanding that it would entirely stop after five years, I would try my damnedest to not let it affect my lifestyle, essentially treat it as an early retirement fund source, and invest it. Perhaps most people wouldn't plan as I would, but I would imagine that the cut off would have a significant effect on at least some of the participants.

I don't necessarily agree that the study is unethical; the participants, one assumes, are told of the cut-off before the start. I do think that the outcomes might be less valid.