As a side effect, if you're legit, not a spammer but are new to HN (0 karma), then maybe one of the paths to getting an RMS is to be able to convince at least 1 non-new HN member with enough karma to stake their reputation and post an RMS on your behalf. Therefore the RMS is already vetted by someone real that's been around HN for a bit.
Crowdsourcing RMS spam control sounds like it could work well. Like how investors stake their reputation by inviting other co-investors, established HN'ers would have something to lose if they posted RMS spam.