Good question! We ban spammers within hours of when they show up. In the majority of cases, before they even get off ONE spam! It's sort of obvious when a new member posts that they have a 2010 Envoy SS, live in NYC, and their IP is in Bangladesh.
In comparison to other forums where you might find 75% kids who love to talk dirty anonymously, who trash talk each other, boast about their prowess in ANYTHING, and spout completely insane claims about their mileage, mods, or budget - we avoid that problem a different way. By being mature (for the most part), calling out the liars before they get up a head of steam, strive for an intelligent and well-researched discussion style, and having a culture that usually doesn't devolve into dick-waving or testosterone-fueled ranting. And forbidding religious or political discussions because they only serve to divide us when we want to find common ground in our choice of vehicles.
I believe we banned more violators when we were back on Trailvoy than here. And (except for spammers) it was an EXTREMELY rare event there - single-digit count on one hand if I remember correctly, over 6 years for me.
The mods defuse almost all situations when somebody acts as a hothead, far short of banning.
The Premium Section, however, is a different story. What goes on in there - STAYS there. People CAN let their hair down. We're just nicey-nice where Google can see us.