I don't see any problem except for maybe the distance between the officer and his sidearm. Was it close to him so nobody could snatch it?
I work on a brigade staff, and I am constantly surrounded by officers with M9's carried in shoulder holsters. I have heard a few people here that freak out, or are uncomfortable because they can see down the barrel of the Beretta.
I personally do not see a problem. Everyone here carries Israeli style. Even if somebody had a chambered round pointed at me in a shoulder holster,I would feel fine about it. What are the chances of a holstered sidearm "going off"?