...and maybe this person with papers was going to be working from home, or going to court the next day; there's a few reasons they could have had that information on their person.
But in a pub? Really?
Here's a quick policy:
"Use the secure VPN to access electronic documents.
In certain cases you may remove restricted electronic material on encrypted media (do not carry the key with you at the same time).
If hardcopies are removed, these must be signed out to you and you must directly go from one secure location to another (which may include your home or other official location).
Failure to follow this policy will be considered gross negligence leading to summary dismissal.
Any orders to not follow this policy are void."
If they had been mugged at the train station trying to get home, that would be unfortunate and they're not to blame. But seriously...the pub?
Either sack the person responsible or sack manager (if they didn't impress upon the employee the need to take basic precautions).