What does parent commenter stand to gain from falsifying their comment? What do you expect to accomplish with your itemized incredulity?
The chance that there was an illegal activity on the parking lot, if it regularly was in use by non-owners, seems even more of a stretch.
You can see plenty of videos online of folks "policing" spaces they don't ACTUALLY have the rights to (usually because they don't like skin color of someone).
I'm just saying, let's take the claims of criminal activity because someone was simply on a parking lot the OP claims to own with a grain of salt. A big grain :)