I have a family member who’s a police officer and she always complicates family seating arrangements at restaurants because she won’t sit with her back to the door or to the kitchen (or any door or entry point, in fact)! But it’s good advice if you’re armed and ready to respond, because one thing the creeps always rely on is the element of surprise.
I always identify the exits and make a note of potential cover. Many restaurants have large mirrors that can allow you to monitor spaces behind you. It is possible to do all this and not be a boor. ;-)