I mean I don't think of your fling trick as "cheating".
The only things I think of as cheating are actual hacks which means manipulating the game files... the cool throwing technique you came up with isn't that at all.
Similarly, I don't think guarding the edge is cheating either, it's just part of the game. I don't condone cheating. I do condone some good cutthroat gameplay, however, all in good fun.
And yes I'm sure it can be annoying in Ichiban with the gas, but the same kind of applies to the ice level because you'll freeze after being in the water too long. But everyone's trying to kill each other that's kind of the whole point of the game. If every time someone got knocked off, everyone took a hands off approach and let them get back in as much as they wanted without interfering, it would make each match substantially longer, and perhaps more annoying and/or constrained as people wouldn't feel the same degree of freedom of choice as they do.
I used to play a lot of Jedi Knight games and there was this understanding that if someone doesn't have their saber ignited, you shouldn't kill them, because if you did, that was called "griefing". That kind of made sense for a game like that because that game gave way to a lot of roleplaying and a feeling that you were in that world... whereas this game is more of just a way for people to unwind, talk shit all in good fun, and relieve stress by going on rampages, especially with the shovel.
It's designed to be a bloodthirsty game. You WANT your opponents to freeze. You WANT them to be gassed. That's totally the point.