IF anyone wants sportsmanship, you must remove all achievement aspects (i.e. money, cars, ranks, etc) from the game. Otherwise the mind will always be corrupted by everyone, any time. We are all corrupted by achievements in the game once in a while, even for a short time. Whether you want those things for respect, power, or anything, it will corrupt and continue to do so until non-existant. OF course, if you remove these, sportsmanship will be a main prospect because all there is to gain without game achievements is friendship, and fun. But you can bet, there will be people who would not want all of those aspects of the game removed, some for good reason, some for greed.
In short: Sportsmanship can't be possible if there are achievement aspects such as money, cars, ranks and etcetera. Sportsmanship from everyone can only happen if the only goals available are friendship, and enjoyment/fun.