I mean, there are certain "Gentlemen's Rules" where there is an unspoken agreement to do certain things in a match. In Melee, these unspoken agreements were things like no CGing in sheik dittos (I'm looking at you, Toast. I still beat you even though you did that, regardless
) and other silly things like utilting to edgeguard in falcon dittos.
But if there is a large sum of money on the line, anything goes, and you really need to do whatever it takes (just play homo) in order to win
edit:
...Maybe that's why I do a lot better in tournament/MMs than I do in friendlies, since I'm not afraid to just play like an *** in order to win in serious matches, rather than trying to hold back spamming too much in friendlies so that my opponent won't start cussing at me
(I don't like enemies, IRL :D)
In my pools matches, I got John! to start yelling out swear words during our matches because of how many fire arrows, rangs, and bombs I was hitting him with, and getting free up-b's/dair kills as a result
I'm pretty sure I even got JCaesar to swear out loud during our MM as well.. lool ><
I usually say sorry after the match is over (usually when I win as a result of playing homo) to ensure there's no bad blood between me and my opponent just because I like being cool with everyone and I don't have any enemies, and would like to keep it that way