Usually a collision in a parking lot doesn't seem to draw much interest of LE, but no or little action taken by OP's LE doesn't make me feel that the 3 foot law is a waste of effort.

Last month, I reported a motorist to our local PD for passing within inches of me, and from my video, it almost looked like his mirror barely went under my flat bar end mirror.
The same motorist just happen to pass me a couple of days ago, but this time, with more than 3 feet of space, and I could see him make several glances into his rear view mirror after he passed me, it would seem that our local PD and the motorist may have had a conversation about close passing.