I don't think that main cause (or even one of the main ones) of low quality posts is due sig campaigners maintaining several alts but because of simple reason: they are getting paid for those shitposts anyway so why would they change?
As a counterpoint to your argument, I'd say that we've seen lots of evidence of members with alt accounts abusing bounties and signature campaigns, and many of those members have been tagged by me or some other DT member(s). I didn't make that assertion with nothing to back it, and you've been on the forum long enough to have seen people getting busted for enrolling one or more alt accounts in a campaign/bounty.And even if that wasn't the case, why not try to do a good job so that your chances of getting accepted into another campaign or bounty are higher? If you're in a 3rd world country and can make more money participating in a sig campaign than you could with a full-time job in your area, don't you think you should put in some effort? I don't think that's an outrageously high standard.
Unless another campaign gets to YoBit levels of spam, I doubt you'll see much restriction against signature campaigns (even if they are run by Newbies, red-trusted, no-escrow, shady platforms).
Yep, you're right about that--and I think the only problem with Yobit's last campaign was that they seemingly didn't have a cap on how many members they'd allow in, and the result was that there were well over 100 (if I recall correctly) members with varying post quality all trying to make the maximum number of posts per day, which also was a lot. There isn't likely to be a campaign like that again....I hope. 
