I think campaign manager have thought it very well before start the signature campaign, they have own rules and requirement to looking for the participants.
and talking about shitposters, I have seen many spreadsheet of signature campaign, there is I found the participants who don't have enough quality post can't be qualify to get the payment or stakes.
Every Good ICO, there we can find good management to manage the project, seem like choose participants for signature campaign. If the management pay shitposters for signature campaign, that's meaning the campaign not good enough, and I think this is a misery for their own project.