One of the reasons the credit markets froze was the hoarding of cash to meet government reserve requirements. I'll bet the same mechanism is hurting GM, too.
Then are we not also talking about effectively suspending government reserve requirements by allowing accountants to overstate the assets of their business?
When GM sold off GMAC, they offloaded the vast majority of their toxic asset problem from their spreadsheet. They further wrote down $39 odd billion of unusable deferred tax credits in 2007, leaving them now with a simple "expenditures greater than income" problem, which we the taxpayers are kindly helping them through. (Ugh)