Point being, I don't think just because you're in a signature campaign you should be altering your behavior, and avoid posting in sections that you would normally.
Users should read rules of campaigns that they are interested in, before applying. One of requirements that they should consider is which boards in which posts accepted and/or there are posts required in special boards, such as gambling, local boards.
You're absolutely right. I remember writing a thread about this issue titled;
[Guide] Factors to consider before joining paid signature campaigns and what you just suggested above was highlighted as one of those factors. Most applicants don't care about this though, that's why i appreciate quality managers that take time to review applicants post history before accepting them into their managed campaign.
A popular example is the campaign manager @yahoo62278, hardly before you see him employ an inactive poster on the gambling boards for any of his gamble related campaigns. I know this because I have been affected once after been inactive for sometime and apply for his campaign although my post quality is decent, got rejected and I'm positive the reason was due to me not been inactive for the last 2weeks on that particular board before applying for that campaign. Someone who was very active than I got offered the slot although my application was before his and i applaud that decision regardless I was affected.