I would think that any member being spammed will tell you they are. I can see what your saying, but i think its best really to limit the emails any member can send in a day, 20 emails are enough i find, you want your members to take part in the site not use it as some email service anyway, unless of course thats what your aim is. Stopping spammers is a hard one because to stop them you have to limit what they do, and in the process that limits genuine members too