Mailbombing Mailbombing is a No-No, no matter what level of aggravation you been driven to. It's just about the only thing on the internet that is both unethical AND illegal.
Email bombing is terminally stupid in any context.
Just ask your sysadmin if it's all right if you email bomb a spammer. If you're lucky he'll let you keep your account after a few grovels. If you don't bother asking him first and do it anyway, you'll quickly find yourself tossed out the door if you're lucky and reported to the police if you're not. They actually had to shut the entire domain down, and it tok some time before they could bring it back up. Abusing the abusers is still abuse.