I never noticed it until I had my email address in a puppy ad. Now if I put my email in a post I use AT or spaces like YourNameATprovider.com. I doubt your spam's coming from RTF unless your email is in your profile or a puppy ad or someplace easily accessible.
I had to shut down one email account that was my real estate email since it was posted on the NAR, VAR and local association, it just got overwhelmed with spam. There are whole businesses devoted to retrieving emails and selling the lists to spammers. Even as we get more sophisticated at hiding our email addresses their methods of retrieving them get better and better.