The two enemies of rubber bands are UV light and oxygen. In a tightly packed and wrapped bank bag, both of these things would be limited. Nicky, Whiskers, myself, and a few others conducted an experiment and demonstrated that in a shaded, low oxygen environment rubber bands could survive intact for several months.
Bill Grinnell, the gentleman who took the money from the bank to the airport, told me that he has rubber bands in his drawer from banks that shut down 40 years ago.