Yes, it seems silly to be dong 302 redirects like that and assuming it's good enough, given the problems Google's had before with 302 hijacking. A "nofollow" attribute on the link following by disallowing access to the redirection script is the better solution.

As for whether or not bloggers will do advertorials, I think that some definitely will. It's no different from mainstream magazines (some quite respected) running an "advertising section" of content written by an advertiser. At least these things are labeled. The more nefarious ones are the ones that aren't labeled as ads.