I would expect, or hope, that if any DT member would take that deal they would not be swayed by the amount received in order to give an honest review. If there ever comes any point where they (the ones asking for the review) starts talking about receiving trust that would be the big no-no. But just for a review, why not? As long as it is objective I don't see any big issues with it.
Well, I guess I could put up an honest review like this "This site was offering to pay default trust members to review it, which I consider shady AF."
Seriously, there is no reason to want
default trust reviewers unless you want something only default trust can provide... likewise, if you want an honest review of a gambling site you'd be looking for known gambling experts, etc.
Imagine if someone put up a sig campaign or an auction allowing only DT members to participate. I think that would be fishy too.
How different would it be if he was only asking for a different subset of people, e.g. people with > 500 merits?