Earlier quoted context omitted.
Do booze shops in the US store peoples id's after they've flashed them (pun intended)?
It seems to me that age verification via ID submission online and the subsequent storage of IDs are separate issues.
We know that very few organizations are capable of effectively controlling confidential information that they're legally bound to keep confidential. Requiring things that are going to lead to large stores of ID images is asking for trouble.
When you show your ID in a store, the clerk generally doesn't retain a copy of it, and if they do, it's apparent because they take the card to scan it... regardless, they can't take the scanned copy and present it at another store, because the other store will detect that it's not an original.