As has been stated numerous times heretofore, the banning of an established member is not done on a whim, and is always the last resort when attempting to address a problem area, or a situation. It is frequently the result of a lot of hashing and rehashing, and is rarely the result of a "spot" decision. Exceptions are the ever lovable "spammers" that join only to spread thier BS around. Those are are dealt with quickly and efficiently, with little fuss or muss, as thier crap is tossed out the door along with them.
As far as locating a specific indescretion...often it is not a specific incident, but rather a culmination of offenses that just digs a deeper and deeper hole. If, on the rare occasion, it is a single indiscretion, it will be of the variety that requires "clean up".
warrrreagl, you are no more responsible for the banning of a member by reporting a violation, than you are for someone receiving a death sentence as a result of your reporting shots fired. You are reporting an incident. It is the moderator's job to investigate the larger picture.
I do understand the curiosity, however. Especially in the case of established members. It's only natural.
Oh, and billege has got it goin' on there.
Have you been peekin' in the back room?
