Can you give an example of this extra security? Having Player B handle hit detection on himself just sounds like a bad idea to me.
Wouldn't this make it extremely difficult to hit players with high latency? Not even regarding cheats here, just like, what if Player B lives in thailand? Them actually receiving the shot might happen like, upwards of a second after Player A fires, at which point they might be 16 feet or more away. This is the exact opposite of favor the shooter.
Another potential issue is that Player B could conceivably delete the remote event, or the script which responds to it, or write a script which deletes bullets as they're created, and now they're completely invulnerable. I don't think there's any server side solution for this. Any client side solution is a just a band-aid which is easily circumvented via a little reverse engineering.
You could handle hit detection on the server, instead of passing that job onto B, and that sounds substantially more reasonable. Yes there are potential latency problems, but it makes cheating harder. Plus you could potentially implement backwards reconciliation to maximize responsiveness.
I understand that this is largely about minimizing network requirements, but you're giving away a lot of control to players. I don't know if this practice is worth the security cost.