Data storage devices (ie: hard drives, memory cards, flash memory in phones, etc.) don't actually delete things when you tell them to delete. They register the sectors which the "deleted" data is on as being writable again and only once they've been overwritten is the original data truly gone. Even then, you can use software to recover that data based on a bunch of things which are over my head and that I'll make a hash of if I try to explain. So yes, this is true. Any companies which handle sensitive data (ie: governments) actually destroy the storage device because it's the only way for the data to be completely irrecoverable. And that's after having used a secure wipe procedure which involves re-writing the drives with null data a number of times after they've been formatted. Then to destroy them, they're magnetized and finally shredded.