What's up with these users?

[E-Man]

Whenever I browse this site, I tend to check the bar at the bottom that shows who is currently online. As of late, though, I'm beginning to see users who are already banned from this site. Since they are more or less incapable of returning, I find it a little odd that they would do this. Also, since I'm curious as to why they're banned in the first place, I decided to take a look at their forum history to see what went wrong with them. Oddly enough, they had no posts whatsoever! Users like Aeroldglada, Appoitili, and wefweaceWeict had no forum history prior to being banned and it looks like they were only banned on the spot.

I'm very curious, though. Why exactly where these users banned in the first place? My first guess would be banned users trying to use alternate accounts, but an admin saw through the ruse before anything happened; however, judging by how nonsensical their names are, I would also assume that they are bots of some sort. Since I have no clues to find out the answer for myself and no one else I've seen so far asked a similar question, I thought it wouldn't hurt to ask.