I have been hearing about this since I started (I think it is 5 years now). However, I don't remember seeing the official answer on that subject. Lots of 'expert' opinions, but no official answer. I apologize if there was one and I missed it.
HiTech did say, that if you register hit or collision on your side, then it did happen. Now, what is registered on your side has to be acknowledged by the server and other party. There are gazillion of things which can happen to packets between two end points.
The usual culprits are BG processes, PF, NAT, Wireless, QOS, asynchronous routes, etc. If I'd had rubber bullets I'd look to net problems firstly and then all others.
IIRC he once said that hits registration goes over TCP/IP rather than UDP, so it shouldn't happen that often.
Also, I have never experienced rubber bullets even though my ISP is RR, I'm behind NAT, hardware and personal firewall, run AV all the times and my Vsync is Off.