There were a times before cipsoft made skull system when people which were killing to many players were teleported by GM's on the Isle of Solitude. Player teleported on the Isle could be punished for mass killing by cipsoft.
The 'Isle of Solitude, also called GM Island, located in the bay between Carlin and Greenshore
I asked some old players more about it :)
What I heard is that when you had to many frags for example you killed on ue 10 people then your account was deleted. Also what my friend told me is that there was a program online where you could see how many frags did you get so you could keep eye on it.