I understand that, and I kindly did tell the user that I don't roleplay. But I do feel that users should avoid inviting complete strangers all together unless they've seen the user interacting in other RPGs. I'm not asking for you to do anything, that's just how I feel.

People are just trying to invite you for a roleplay. It might be annoying, but I don't think it's worth a warning. It's not their fault someone doesn't want to talk or rolepaly with them after all, just ignore or kindly decline thier request.

However if the same user keeps nagging you and repetatively sending you roleplay/friend/etc requests - you are free to report that.