I know I am not a campaign manager but what do you think about deleting the rejected signature campaign’s applying? Those applying are there just as trash posts consuming recourses. Also it could be a good thing because when a possible advertiser find his/her post deleted he will know he was not accepted to the current signature campaign.
Some opinions.
I don't think we should force this on people or make it a rule but if campaign managers wanted to do this they would have to self moderate their own threads and do it themselves. Whilst the posts serve no purpose I don't think it's imperative that they're deleted either.