Years ago I was working the grave yard shift at a convenience store. Two black guys pulled right up front and didn’t get out. A customer was checking out and I asked him to hang around and pointed out the two black guys. He advised me to pick up the phone and act like I was making a call. I did and the two guys left. Later that night 3 convenience stores were robbed.
I’ve been in a neighborhood bar where the bartender would simply lock the door when it was being cased; anyone who wanted to come in could knock and be let in if recognized, and anyone else could be told it was closed - what were they going to do about it? Once they sent in a female to ask for change for a bus long after they stopped running; the bartender made change, followed her to the door, and locked it right behind her.
Smart move on your part!