Every site gets it's fair share of trolls, unfortunately on this particular website, the mods can only ban accounts rather than IP addresses. This of course means that as soon as a person gets banned, they can just make a new account and come back straight away. And this happens... A lot.
Most of the time you can't really tell it's a troll since they use a different name and act like a normal, non-trolly person for awhile before going back to their old, trolly ways. On the other hand, some people will come back to the site and openly admit that they're the troll that just got banned. Some (or at least one) will even use the same name over and over so you know exactly who they are.
Still, returning trolls don't usually seem to get banned unless they start trolling again. I remember when I joined the site, at least a couple of people admitting that they got banned for trolling on the site when they were younger, but since they got more mature, nobody's bothered by them anymore because they stopped trolling and started contributing. That being said though, the reason trolls can return to the site isn't because we're secretly hoping they'll come back and change their ways, it's because of a flawed website where the mods don't have the ability to ban an individual from the site for good.
So I guess what I'm asking is... Should we wait for a banned person to start trolling before we ban them again? If we know that this person isn't supposed to be on the site, why do we wait for them to do something wrong before banning them a second time? Does it matter if they pinky swear they're going to stop trolling now? Should we wait around and leave them to it and only ban them if they actually start trolling again, or should we just ban them straight away on account of... They're already banned?