I was head of store secrity for a time while attending college. Every thief we caught (shoplifter, bad check artists, stolen credit card user, vandal)and convicted got their picture posted on the wall. I overhead some customer say say “Jeez, don’t F around in here! There are 200 apprehensions on that wall!” Worked like a charm. In four years the loss rate down to less than 1%.
Most stores try to strike some balance between unfriendliness and security.