I don't think anyone will disagree with you. The OP should have covered these options earlier if he didn't have enough margin handle an assignment. IB should cover the position to protect themselves. But if they can do it in a manner that saves the customer money at no extra risk to themselves, shouldn't they do that?
You know, the greater point of my post was not clear -- it's morning, and of course there's lots going on. (That's my excuse: I'm stayin' wit' it.)
The thing is, it's not IB's call, to autoliquidate to our advantage or desire or prior-stated preference or whatever. It's just their call that we've fouled up, and they're going to send a notice ("Hey! Big Red Flashing Stuff Means Address Account Deficits!") and then 30 seconds or 5 minutes or 50[!!!] minutes later, they deal with it if we haven't.
(Not that I make a habit of this, but) I have seen IB buy stuff far away from the market, giving liability closer in a chance to "recover" cuz *surely* the market will be turning. And I have seen them take stuff right in the teeth of it, *just*as* the market was turning to make it all better. And I'm sure I've seen them take stuff by buying back shorts for a $1 that would become shorts for $1.75 two or three minutes later.....
My preferences each time would've been (in fact "were entirely") situation-specific. Portfolio-specific; *market*-specific. If IB has 10,000,000 accounts, of which 0.05% are sitting on the cusp of autoliquidation at any instant -- that's 50,000 accounts. In a market swing? Multiply that by 10.
If you were an IB shareholder, or an IB regulator, would you want them to be interrogating the specifics of each of those 50,000+ accounts, to find patterns, entirety of inventory, stated "Liquidate-last" columns, etc etc, to muscle through and find which of the current holdings to pluck first? Egads.
Their business is to mind their books; OUR business is to mind ours.
When your actions force someone else to take the wheel, don't bitch cuz they didn't take you home. (And, that'd be my point. Thanks for reading this far. I think I wuz writing to my younger self.....)