Or is it perhaps waiting for a hostile enco to wipe out your caravan in order to then loot the dead NPCs?
Sneaking and waiting for loot, this is all I can think you could get banned.
If looting NPCs is ban-worthy then the entire server should be banned.
Here's the "exploit" I got banned for:
1. Join a caravan.
2. Encounter the new ridiculously OP ghouls.
3. Let the ghouls wreck your ridiculously weak caravan.
4. Drag ghouls away from the bodies of the dead caravan guards.
5. Go back and, "exploiting" the fact that ghouls are slow, loot the dead bodies safely.
I had absolutely no way of knowing that it was not allowed. More than that, I still consider this to be in no way harmful to the game and absolutely not worth a ban.
Also, I was in no way warned by the GM not to do what I did prior to the ban being issued.
It is therefore completely obvious to me that I was banned not because of this so-called "exploit," but because of some sort of personal grudge that the GM that banned me apparently holds against me. I have no clue what that grudge may be, as I don't exactly keep track of every noob I might've offended at some point, but I find such conduct of the GM to be absolutely inappropriate & unacceptable.
That's about all I have to say about the matter.
Good luck keeping the server up & running with GMs like this.