I agree with you, unlike other campaigns, the company sends payments into the casino accounts of participants, this means they can easily check who are real active gamblers interested in the matter who would post in the gambling section even if they were not enrolled in a casino campaign and who are non-gamblers posting there just because the campaign is requiring it.
To be fair: gambling away your earnings isn't smart. It makes sense that some gamblers join a signature campaign to get more gambling funds. But recruiting campaign participants doesn't happen on Stake, and I don't expect the majority of Bitcointalk users to be active gamblers.