I do think that a lot of this kind of thing is pure adrenaline. I know I don't feel hits very well when I'm fully on edge - it's the main reason I've stopped wearing vests, because i feel hits a lot better through just a shirt. But then again, I have to take a lot of pain medication to be there at all, so perhaps I'm not a good example. Still...
...one of the last times I was out, a person was on a major adrenaline one over getting knife kills. His technique was to just sprint at us... which, as daft as it sounds, had done quite well earlier on, because he'd go for high speed flanking maneuvers then be on you before you even noticed he was the enemy - he got me that way once and i heard chat that it had worked plenty of times. So, by late afternoon, the whole trip was going to his head - he sprinted at us through a doorway in the Fort @Skirmish, Budby site - I'm pretty sure that the lad stood next to me shot him with his AEG the moment he appeared in the doorway, and I know for a fact that i double tapped him with my pistol. There was no possibility of a miss - I was already aiming at the nearside of the doorway as he came through it at exactly that spot - I just had to pull the trigger. Because he argued that it was a 50/50 I fired into the ground to make sure it was loaded and working - it was.
For it to have been 50/50 he would have to have been moving as fast as my BB's for 2 metres-ish having just changed direction to get through the door - my hole. I know what happened. All of us stood around that doorway know what happened, except apparently the knife kill wonderkind, but although he refused to accept that we had shot him first, he took his hit and did not call a marshal. Looking back I realise I should have, but I just ignored it and carried on with the game.
For me if there is reasonable doubt I'll always take the hit, but when the same person seems to be relying on my sense of honour to get inside my AEG's outranging of theirs by sprinting towards me while i'm firing at them, so in theory i could be missing, then taking the hit when their effective range is reached (and this has happened a number of times) then I feel that the reasonableness of the doubt comes into question.
Part of my thinking is that I don't fiddle with my AEG's and buy upgrade parts for them just so that I can ignore the range advantage, in order that I don't offend anyone, and take any old dubious hits to keep the peace. But then again, if a marshal wasn't present so they could make a decision based on what they actually saw, what can they say except 50/50? I believe that when people know they are pushing their luck they'll not make a big deal out of it. If they do make a big deal out of it, then either they genuinely believe they are right, in which case i have to sympathise with the marshal, who is in an impossible position, and take the hit, or they are a bold faced liar, in which case having brought it to the attention of a marshal, they are unlikely to get away with pushing their luck that way a second time. But that is it though: I play responsibly so I trust my senses unless my opinion is challenged. What else can we do?
As Ed says though, good marshalling is essential. We have to trust the marshals so that if we do take a hit under dubious circumstances to keep the peace, they will not only keep an eye on the players involved, but remember the details of what happened and, if it happens again, not be inclined to dismiss it as a simple "don't know = 50/50". It is an unfortunate fact of our game however that the quality of marshalling is not consistent and that there are people who who do not simply push their luck, but blatantly cheat. In the face of the perfect storm of dicks for marshals and dicks for opposition, my enthusiasm for the game fails.
It has only happened to me that bad once - I did leave early. Unfortunately I did not come to that decision before resorting to the same dick tactics - on one occasion ignoring about 5 hits to pump over a full 100rnd mid cap into the target - it took that many shots at someone less than 30m away to get him to finally call hit, which is to ignore the 2 other times i'd gone up against him in the same position and taken my hits and the several team mates who had done similar - yes he was surrounded by undergrowth and bushes, but so were we, so he was either the luckiest bastard to ever take the field or cheating his arse off. But the thing is, once I had done that, even though we could progress, I didn't want to play anymore. If there are no rules, there is no game. Why bother with tactics/cover/the effort to make your guns better/etc when you're just going to refuse to take your hits? Where's the challenge?