Is there any limit to join in signature campaign in bitcointalk?
How many campaign allowed?
The forum itself have no specific rules regarding this. If you mean the ability to join multiple signatures campaign at the same time then no, campaigns usually ask for users to only wear their signatures otherwise they don't get paid but If you mean enrollment into different campaigns using different accounts then, unless you are not spamming, you should be fine.
You're just conveying him that having multiple accounts in different campaign is okay, unless you did it too. And having multiple accounts joined in different campaign spams the forum, how can they do that in a matter of time? Of course they will spam to enable to reach their quota.
And to OP the answer of your question is no, there's no campaign will do that. You can only join some avatar and personal text campaign unless the campaign you participated allows it.