I think that there are several ways of looking at this.
Before a person may be deemed to "cheat" you have to assume that there is a set of rules, that the player knows and has agreed to play by the rules, and then has chosen to consciously disregard one or more rules. My experience is that a person has to take golf fairly seriously before they take the time an effort to learn the rules. The commitment to play by the rules is a personal choice.
Before I started playing golf on a regular basis, I would play casually with several friends. Some groups would allow a mulligan only on the first hole, some would allow one mulligan per nine holes. Almost always someone would improve their lie by rolling the ball a half turn forward and the like. OBs were treated as lateral water hazards. I think these forms of "cheating" are fairly common among non-serious golfers. As long as everyone is OK with it, who cares? The point is to have fun, and we did.
When I started taking the game more seriously, I was shocked to learn that there is no official mulligan rule. Moreover, I think that the rule which requires a person to play out of a fairway divot that some joker rudely chose not to replace is completely unfair, and finally, the last thing I want to do on a busy day on a busy course is to walk back to the tee box with the next group waiting after I discover that the ball which I thought to be on the course has in fact rolled 1 foot into someone's backyard.
That said, I now post scores for handicap purposes. Each and every round I post is played strictly by the rules. It makes no sense for me not to. Also it is a good way to chart your progress (or lack thereof).