Valuation lower than assets means you get eaten by corporate raiders, unless you're as big as Ford or the majority of the stock is held by a single family. That just shows how unhealthy Ford is.
Although there probably is some way to siphon off the assets and default on the debt without committing fraud.
PS: Actually it's not so simple - when the company is highly leveraged, existing bondholders often do have a say in future financing decisions of the company.
This doesn't happen if the raiding company can't put together enough money to make the purchase, or if not enough of the stock holders are willing to part with their shares.