I don't agree with icopress's above statement at all.  It might be bad etiquette to bad mouth whatever you're advertising in your signature space (and it would certainly cause a bit of confusion/head-scratching to anyone who might not know much about sig campaigns), but requiring members to mention the product/service in their sig space if they're engaged in a discussion about a set of products/services in which it belongs is just not good--unless that sort of posting is explicitly prohibited in the campaign's rules, and even then I think it's crossing a line.

No.  Any issue like this should be a matter between the campaign manager and the participants.  There's no way Theymos would institute a rule of any kind dealing with how members should post when they're advertising stuff.