Well, first off, you dont get banned, you just get kicked for an illegle action, and gms are informed, of which, gms arnt informed, and you never get banned because the gms arnt informed...the only way you get banned, is if you go yell out something stupid such as
"HEY GMS SCAN ME!!! I AM A TYRANT/TREASURE HUNTER MULTICLASS!!! YAY!!!"
Or, you do something else thats equally stupid...
As for finding a server thats crowded, a couple of the ones listed on this site have a few people playing, i've been on a few that are 50+ and even a few that are 100-150+, so, you could always use the good ol search bar, because im not going to do you any favors by posting a link to the urls.