One of my favorite rap lines goes like this:
"Now who ain't goin home? Looks like you
You hear strike one, talkin ****, strike two
Won't be a strike three, cause I don't play fair
I'ma look you in your eye while he hit you from the rear"
(DMX - No Sunshine)
To me, the line is staying that the rules don't always apply when the game is on the line. In a life or death situation - there is no such thing as cheating, you do what you must to survive.
In sports, it's another matter. For example, in football it is the job of the officials and opposing coaches to recognize rule infractions and mistakes to keep the game fair. If a tailback's foot goes out of bounds, if a quarterback fumbles a football forward three yards within the last 2 minutes of the game and recovers - the referrees must make the right call. If they don't, the offending team ain't gonna just own up to it until after the game is over. On the other hand in golf - there is an official who knows the rules, but you are expected to enforce the penalties on yourself, a true game of honor.
Fencing is somewhere in between. It is considered a game of gentlemen, but it's origins are from the life or death situation mentioned above. There is a referee who must know the rules and dole out penalties, but the fencers are expected by custom to acknowledge touches received both in practice and even in competition. If you refuse to acknowledge an obvious touch, it leaves a bad taste in the mouth of all who witnesses such dishonesty. However, if you land a touch during a less obvious corps-a-corps, then arguing the touch was before the contact is simply part of the game.
When I fence, I can be physical, and I have a strong knowledge of the rules. Plus, I observe the behavior of the referree. If I feel the ref can be influenced, then at the right moment, I will do my best to take advantage. I don't feel that is cheating - it's just part of the game. However, if a wild remise grazes my ankle on a wood piste - I am going to acknowledge and accept the touch, anything less would be dishonorable.
A couple years ago I fenced a very tough local tournament at Vanderbilt. We were in DEs, and I was fencing an older teenager on the gym floor. He was tough, but I landed a foot touch and he refused to acknowledge it. The crowd laughed when I let go my epee, and it stood up inside the kid's sock. Not only did I get the touch, but the kid rightly felt like a fool, and he lost any credibilty with the referee. In fencing, especially in foil and saber, crediblity is everything. In epee fencing on a non-grounded piste, credibility counts for a LOT - especially if the referee is inexperienced.
I am no Dudley Do-Right, so my gauge is this... If the touch plainly landed on me, so that I could see and or feel it - I acknowledge without hesitation. Often I acknowledge wrongly because I was able to lock out the computer with my own touch a few milliseconds before. If the referee disagrees, I will plead my perspective once, and then let it go. Of course, if it is a touch in my favor I would plead my side as much and as loudly as I can get away with, without hurting my chances. If there is an honest question on the touch being scored against me, I will remain silent and let the referee sort it out. And if I know I was not touched or the touch was not valid, I will protest vehemently.
The worst is someone who refuses to acknowledge a valid touch - the only solution then is to request floor judges, or just hit harder.