It just so happens that in proximity to me a vendor got busted and it turned out he kept tables full of his order informations - not only the dnm account name and the order details, but the unencrypted customer informations like name, address etc. too, ranging back for years. This of course led to countless further cases of prosecution.
If you're vending, don't ever do that to your customers. Don't keep permanent records at all, and if you really need to keep additional digital records make sure to securely delete the files on a regular basis.
Please, don't fuck over your customers like this one guy and probably a lot of others I don't know about did. It's really one of the worst things you can do in this business.
I would imagine it would just prove more deals and tack more time onto your sentence.
Probably kept out of pure laziness