Wanna bet? Check with your ISP, ask them how they deal with spammers.
Spamming is technically considered illegal.
Also, when you're banned from a site, it means you're not allowed to go there, ISPs don't enjoy getting reports, as they're responsible for all their users.
So reporting a user means they'll deal with them, though sometimes they give you X chances, but may block you from certain services/sites.
The internet isn't your playground.