A person behind hard cover might be OK unless the turret fired rounds that pierced the masonry walls. Which would be awesome, though it would result in the whole neighborhood looking like swiss cheese. If the turret fired lower-powered ammo the shooter could fire then drop, allowing return fire to strike his cover. But a person crouched in some bushes firing repeatedly would be toast.
Again, it's area-denial. You wouldn't set these up if you had troops in the no-man's-land, and your people know to stay out of the area.
I sometimes wonder if we're gonna see Identification of Friend or Foe tech on the infantry level. You have access to a map of the area, all mobiles are marked if spotted by a combination of aural sensors, drones, satellites, and the security camera network. Their faces are also automatically searched against a database, and either marked Unknown or Enemy depending on whether he's in the database of soldiers / police / terrorists / criminals as being part of the "other side" in that engagement - although anyone with a friendly RFID tag counts as a Friend, if an Enemy has a Friendly RFID tag it flashes a special warning. Basically saying, this guy is either a friendly operative who still has a record, or he's an enemy combatant who picked up some of our gear.
If an Unknown fires a weapon he's marked Enemy. Your police is pretty much that if you're a civilian in a warzone you need to be registered as a friendly combatant or an enemy combatant, and if you shoot without doing one of those things, we assume you're an enemy. You could be shooting our enemies! But we don't know that because our aural gunshot-detection tech isn't perfect.
Sure it could let people disguise themselves as part of your side, and it could let them track your men - but uniforms do that already. This is like an invisible uniform. And as long as your side has better access to the RFID tracking tech and GPS mapping, you have the advantage.