The thing is that even if you agree to use sleep bombs you cannot be certain your adversary won't either. Then, it can also be the case that gas-masks can be used which would render sleepbombs pretty much useless. I think it wouldn't even be that hard to make a sleepbomb.
Good idea tho, just think that others may not be so peaceful.
RE: Is There Such a Thing As A Safe Bomb? Yes, Paradoxical but Possible!