Yeah, what do you do when you know full well you did shoot someone first though? I mean sh*t, there's no point arguing because a marshal would have had to be standing right next to you to see exactly how it went down, so they are obviously going to go with 50/50 as the way to prevent a row.
I'd just once like to see a player own up to having failed their sneaky maneuver when they pop round a corner to shoot you, but you were aiming right at that space so all you had to do was press your trigger to hit them with your 1st BB, before they could even acquire you as a target, let alone fire! I spose it's because people get quite emotionally invested in the win when they have had to take, perhaps a whole series of, risks to get up close where 50/50's happen. Rather than row I've given a kiddie with a rubber tomahawk a 50/50, even though I was about 2m from the cover so he had to run towards me while i was aiming my pistol at the doorway, then him specifically, but only the once. That particular kiddie was constantly trying it on and seems to think that just talking over people as they try to explain that since he can't run at 350FPS he must have been hit first makes him right...
I expect that to some people, seeing me refuse a 50/50 must have made me seem like a bad sport... especially when I've said things like, "You can f*ck right off, mate!", but what can you do?
Happens to me every-time i play CQB. I've been hit first and told the opp not to bother taking it, and I've ignored return fire from someone clearly hit first. More often me telling them not to take the hit as no risk of death and infinite re-spawns makes diving round a corner frequently seem a good idea
Anything seemingly simultaneous is a 50/50 ofc, but as you say it often isn't. The cut-off point i try to use is that if someone has to continue to move/turn at all to return fire after being hit then you clearly hit them first and vice-versa. In my mind this is the difference between someone not being able to stop their reflex action of trying to shoot you quickly enough after being hit, and a true 50/50 moment. I am able to tell when my return shot was a too late reflex action, and so can most unless they're too clad in combat clothing to know wtf is going on.
I figure this is the conditions that make the difference in real life, someone not moving is more likely to squeeze off a shot themselves in the vaguely right direction when they get shot.
This means I'll consider myself on the loosing end of a 50/50 if bursting round a corner to an alert defender, but doing the same to someone who is distracted and/or not facing me directly puts the ball in my court.
Usually if it's me getting hit by an alert defender (most often) I'll try to at least say hit first, if it seems to be 50/50 i'll leave the opp to decide, usually getting a kill is satisfying enough for them to follow and take the hit too. If it seems a shot too late from me i'll tell/congratulate them.
Only issues I've had is with people who don't realize they were hit at all in a 50/50 ish moment, or when they've missed from 2 metres with a pistol (surely that cant be possible, right?! i must have hit them!)
Most funny one i had was when myself and an opp jumped round the same corner simultaneously, colliding with each other, both fired and both managed to hit each others gun with tracer BB (nice little splitting BB firework show). We agreed next time we should try to shoot each other's BB's out of the air, and both took a hit as we'd already interrupted play by pausing to gather wtf had just happened