That's what being a mod should be.
Walk softly and carry a big stick, like the saying goes.

Set an example by how you act in the forums and just do what ya normally do. When somebody gets out of line or posts spam or whatever, go in and edit their post or erase it, then if it's really bad send a private message to the guy. Most of the time, I'll just go in and move a post or erase a few words or whatever.
If the spammer still doesn't get it and keeps acting like a jerk, ban him.
Then from then on we can track his IP number and he'll never post here again.
Then if he tries to keep signing on under different names we can contact his ISP and file an a abuse complaint. Most places will cut off his service.

Most times it never gets to that though. Guitar Tricks has a reputation for being a place where you can actually have intelligent discussions without worrying about jerks ruining it for everybody else.