Chrysler Repair: fact or fiction, erasable memory, dodge intrepid

Question
a technician claims the pcm on my 2001 dodge intrepid has been erased because another tech unhooked the battery wiping all blocks of data. Does this really happen or is the pcm just like my usb retains data and is viewable upon demand?

Answer
when u disconnect the battery  all of the flash erasable memory is lost like all the tests and codes that are stored when the light comes on or when u haft to pass state inspection.
As for the main software no it cant be erased just by undoing the battery