I ain't saying a proper host is providing a field and setting up an 18 hour game of capture the flag and hoping someone is bringing a flag. They definitely bring the props, pyro, food and story.
HOW the players negotiate their way through those things on the field is up to the players, though. I'm not saying they have to bring the setting of the game. They have to bring HOW they play the game with them and that's where I believe the difference is.
I've seen two teams play against each other with completely different styles. One side scattered and played with no organization at all, just gagglefucking with no plan. The other side organized and communicated, had a clear chain of command and leader, contingencies and such with an overall plan. Contact reports were passed up, orders were passed down. You can guess which side was subjected to a thorough seal clubbing.
That's why I say milsim is what is brought by the players. I might meet you halfway though and say the players are equally responsible for the milsim aspect of the game. I mean, what good is a bitchin' scenario when you get a dozen randomly-firing newfags who show up in jeans and t-shirts all of who are carrying stock sniper rifles and they crap out in three hours because they're getting plowed hard and put away wet?
Age Verifier - Lower Vancouver Island
Brotherhood of Nod - Nod Prime || Vancouver Island Airsoft League - President