Colin,
There have been a few ... mostly those who continue to think that the forum rules do not apply to them, especially after repeated warnings from the forum staff.
Bottom line is that we do try everything else in the world before issuing that kind of punitive action. As a last ditch effort, we might issue a temporary ban for a week or two - in hopes that the offender will mend their ways. Most do, after seeing that we mean what we say. Those who don't ... well ... they can't say that they weren't properly warned.
Spammers, however, get the permanent boot right away - we have a zero tolerance for spammers on this site.