I use Yahoo mail, and in my inbox at the top of each email I can click if it is "spam" - and in the spam section, I can click if it is not spam. Is there anything like that with your system? I do always check my spam folder, though - you never know when something goes in there that shouldn't.
Regarding receiving from RVnet, I actually don't do that - I shut off email notifications... I just go to "My Forums" when I come here to see any new posts in threads that I participated in, then after going through that go to "Active" to see newest posts.
I don't know if this helped!