I've definitely had more good experiences with this than bad. At Hot box, there was really only 1 close to frustrating time. I shot a guy a few times, and watched them clearly hitting him. He stopped, looked around, then started to run away. I shot him again and he finally called himself out. I took it to assume he just didn't feel the initial hits and just heard gunfire.
I actually hilariously ran into Arnold in building 2, just before the no-respawn phase of Hot Box. He came up to me pointing in the direction of my team telling me there was a guy there. I looked at him for a second and said "But I'm not on your team." And took a few shots at his legs before he turned and got me in the chest. I took the hit, but pointed out that I tagged him in the leg as well. He said he didn't feel it, then looked down at his thigh pocket seemingly remembering the big bulge in it, looked like a book maybe. Said he probably just didn't feel it and took the hit as well. We laughed about him being confused by my multicam looking green and we both headed back to respawn. Definitely made me more respectful of him and it was great to see that kind of sportsmanship despite being an "enemy".
But as a few have pointed out, for the most part it's good, aside from the few hot heads here and there.