“Oops. Accidentally set the shredder to ‘scan’ instead of ‘shred.’ My bad!”
In the digital age the destruction of data is a really complex process.
A lawyer is going to multiple digital copies at different locations.
He will probably have both laptop and desktop computers synced together.
Will have off-site backups and possibly on-site backups.
If it is really important, he might have it on thumb drive or DVD hard copy it a safe.
So, it might be very easy to forget to destroy one or two copies.
Then there is always the possibility that someone hacked your computer and stole the data.
These things happen