Oh, I know that feeling... Back in about 1994-95 I picked up a deactivated Bren Mk1 from a shop in London (Angel Islington I think), it was in a long cardboard box but it was still in the IRA era and I must have been sweating buckets carrying this on the underground, once I got to my destination station Euston (again I think) I went to the transport police to ask if they wanted to hold on to it till my train to Edinburgh in a few hours. Their answer was no, just leave it in left luggage.
I was astounded TBH.