Or it could be muscle memory. Break, Put Seat Down, Look, Break, Put Seat Down, Look......
It probably won't even cross his mind to look first to see if seat is down. To make sure he would look first, you really have to roll down the back windows a few inches.
When our MS was broken into, we shared dashcam footage with a fellow Tesla victim curious about the guys who had victimized our cars. The team of guys in his case in a Costco parking lot at night were all peering into the windows before they took any action to break a window. I suspect they do take the time to look.