As noble as you're idea may be - and I really do believe it is -, it's probably not the best one. I've seen a lot of newbies recently who've gotten Merits for a few posts here and there, where the Meriter hadn't really looked any deeper in the newbie's post history. As soon as these guys reach Jr. or Member level, they join a campaign, at which point they start flooding the forum with spam. I don't have to tell you that many of them are here for one reason only: bounties.
I'd warmly recommend you to do at least a minimal quick check of the poster's history to make sure it's not a complete shitposting spammer who had one lucky shot. Otherwise, you might be unwillingly sponsoring a (future) spammer.
Just my 2 cents. Once again, I think your idea is noble, and you're completely free to do whatever you want to with your well-deserved sMerits.
Your observation is spot on. Some of these newbies just want to rank up to enable them find bounties. It's not that they're serious developing on the forum. However, some bounties don't rely on the rank but activities of the user to allow them enroll. That goes to show that most bounty managers don't give a hoot controlling spam and shit posting on the forum. All they care is to fill their spreadsheets to please their paymasters — the project teams.