Yes, I agree -- but a sig guaranteed is a failsafe for which IB is not liable (bec the bank/brokerage issuing the guarantee is liable and bonded) up to the dollar limit of level of the medallion. So I am proposing it as an absolute backstop which provides little exposure to IB from claims of theft.
If IB wants to be more generous, take on some risk, and offer an all electronic/phone failsafe way to get money out in a guaranteed timeframe, all the better. But other mechanisms don't have a 3rd party taking on the risk of fraud like a medallion sig guarantee does.
As to trust -- I have almost full trust in IB or I wouldn't be both a customer and supporter. But it cannot be full bec the present policies/agreements do not provide a basis for seeking damages due to an error that delays a withdrawal inordinately.