Well, i kinda understand people finding annoying the topic, either because they hate the b content or the topic come back again and again.
But on the other hand, hey, reading every message is not necesary, and sometimes new people join the discussion, so its normal to ask
Anyways, i think about two possible options
The first but not... Optimal (because some people don't read xD) is what You guys already said, a disclaimer in the OP
The second and more interesting and definitive option is doing a specific fanart thread or a mod version, obviously its way more complicated than the first option, but, i'm almost 100% sure that people would stop asking