In the years I've been there, I've not seen anyone servicing a loaded gun (!). Yes, one time I saw the first guy coming in on a Sunday morning forget to turn on the red light. I doubt that this happens only at Target.
I worry more about the members who bring in guests, and then don't supervise them directly. They shoot in one lane, and leave their buddy (or girlfriend) to shoot in the adjacent lane, unsupervised. THAT worries me. I bring in a good number of guests myself, trying to promote shooting, and I am always within arm length of them, keeping an eye on where they are pointing the gun. I actually left the range one time because of this issue. But I think this will be true in any club that allows members to bring guests. And there are some awfully stupid members as well.
They bring in lots of small groups, which are supervised by staff, and I'm much less nervous about this. The store staff supervise their shooting tourists fairly hands-on.