How Real Estate Scams caused worry among investors?

obviously, if you're investing in the real property, and you're being scammed, you'd be worried about your investment.  However, investment bankers often bundle mortgages of many properties, and they sell the mortgages as an investment.  If the properties behind the mortgages are worthless, then the property owner will default the mortgage.  IF I have a $500,000 mortgage and the property is worth $100,000, then the bank out $400,000 when the owner defaults.  IF I'm an investor that has bought a package of these worthless mortgages, the the value of my investment deteriorates.  I lose money big time.   This is what happened in the great recession of 2008.  The bankers approved a bunch of mortgages for people with poor credit records.  When people began defaulted on the mortgages, the bundled investment packages lost their value. One problem, was the investors who bought the bundled mortgages, had no idea of the property they were backed by, or the quality of the mortgage holders.  This was largely brought about by the government, who pushed granting mortgages to low-income people who were not credit worthy.