I've only been through the Canadian equivalent of Chapter 11 and that was in 1993. Everything ordered from vendors during the Chapter 11 period was pre-paid before shipping. No payment, no shipment. Also, some suppliers were so pissed off after Chapter 11 that they refused to do business again outside of Chapter 11.
In the event that even an "orderly bankruptcy" is arranged, would the secured creditors not try to liquidate existing stock as quickly as possible to recoup as much as they can? Would this mean that a massive "fire sale" would happen?
Also as part of the restructuring would GM be forced to close down even more brands than those recently proposed to the U.S. government?