Pensions are Federally insured (PBGC). As for 401ks -- the custodians aren't at risk. So are you asking, "What if I make a bad investment in my 401k?". You lose money. Investing in a bankrupt company would be a bad investment.
Maybe it is time people paying into pensions and 401k's begin to understand they are scams enshrined in law to prop up the financial industry.
Maybe if mainstreet stopped giving their money to wallstreet to mismanage in the first place there would be no need for future bailouts to begin with as wallstreet runs a muck with pension and 401k funds. These are the very same bankers who continued to buy toxic mortgages in 2008 with Client funds as the banks were selling off any positions they had in the very same assets.