Back in the mid-80's my company produced financial software for Apple II computers. Some customers at a Xerox Business store were having problems and thought their data was corrupted. We requested they make copies of their disks and send them to us for analysis, and to make sure to package them against damage. Several days later we received a large envelope with 2 pieces of cardboard and sandwiched between were several photocopies of the front and back sides of their floppy disks.