Creating a fair level playing field for all players is a very difficult thing to do mainly because of the reasons pointed out by both Das Bose and r0tzbua concerning what people actually do versus what you want them to do in order to create that level playing field for everyone.
Where you win because you were actually better than the other team and not because you removed the smoke and they didn't even know it could be done.
The reality is more often than not as r0tzbua has stated due usually to a very small minority who feel its justifiable to use every means possible to subvert rules or settings if they are not specified in detail by an adjudicating body such as a league or ladder.
Which means that you end up with a situation where the rules and settings by ladders and leagues go into great detail in order to avoid any confusion or loop holes and if possible force players via the use of server restrictions or mods/mutators to play to those rules.
More often than not even if they are specified they are ignored until that player is caught or in some way discovered.
At which point they then begin the process of claiming "everyone does it" or "but it was not specifically stated I could not do it" or my favourite "Your rules suck".
Yes it may appear naive for the admins of tournaments, leagues or ladders to want players who compete to play with a degree of sportsmanship and fairness towards their fellow competitors in a video game but in reality it is an aspiration that the overwhelming majority of every games players express when competeing even in a friendly match.
"Can we all play with the same settings (within reason) and enjoy a game where the winner wins because he is actually a better player."
These forums are no different to that of many other games where the vast majority wish to see parity within competitive matches so that results are based upon the skill of a teams players and their abillity to work as a cohesive unit and NOT upon how well a their knowledge of the engine allows them to unlock, turn off and generally mess with the game to degree that the only thing left to see is the opposing team standing naked at the end of the map, who meanwhile actually think they cannot be seen because they are hiding behind that wall.
As I have said many times before "Just because you can do something is not sufficient enough reason to do it"
Life is about choices, so claiming I stole the car because the doors were open or I stole that money because the safe was unlocked, whilst being extremes and being actual crimes, none the less leave those effected by players who deliberately go out of their way to circumvent rules and settings with the same reactions as a victim of such pretty crime.
Angry, cheated, robbed and victimised.
Therefore I personally have no sympathy with any player who feels its "ok" to "exploit" various game engine loop holes or "sneak by" rules or settings especially in competitive match play.