A touch of grease under the plastic caps keep them on if they are loose.
I have kept my locking bolts for the moment. I think the 18 inch Hirsch wheels may still be an attraction to someone. But on the smaller wheels I would probably do away with them. On the odd occasion I let someone change my wheels, I have managed to swap the locking bolt for a plain one before taking it in to the garage. I don't other at the Saab place as they are usually very careful.
SWMBO still has the BiMecc locking bolts. A bit of security, and they can be easily (I hope) be removed with the hammered on socket.