Quote from comintel:
Exactly right.
IB believes they can control risk so firmly in real-time that they freely accept company trading accounts without personal guarantees on the belief that they are never going to allow debit balances to occur in the first place.
You can bet this means that they have many many accounts whose owners will take large risks.
IB knows this and therefore has to implement significant margin increases, and, as you say, automated liquidation, very promptly when the markets get wild, which they certainly do.
So one might face automated liquidation a lot more promptly with IB if markets get really wild, as well as trading limits. Well, we know that too I guess.
I still prefer this way , a limit on margins when things are wild then them coming after my personal assets above and beyond an LLC