The DMCB did a literature search to disprove either of these arguments. It was unable to find any.
And then there is the inevitable gaming that can go on. Persons may 'join' a fitness club, not go and keep the money, requiring the insurer to impose requirements with or without monitoring to make sure the letter and spirit of the initiative is being met. That may be one key difference vis-à-vis a Federally-run program: the 'clunkers' program seems to be quite game-able.
Cash for clunkers... meet cash for slackers.