I believe that each member here wearing a signature of any campaign without getting accepted or following the rules set by the campaign manager is mainly representing himself, while when another member is following the rules he wouldn’t be spamming otherwise he would get fired and removed from that campaign. Bitcoin campaigns are not allowing or encouraging spam, quite the opposite they are all against spam.
Probably, from what I have seen, most spammers are the ones wearing altcoin’s signatures, since most of those managers are newbies with new accounts and red tags, not known or trusted among our community.

The campaign managers are not responsible about other members wearing their signature without getting accepted, at the same time you can report any spam post you see in the forum regardless what that member is wearing.