lots of people going Sssshhhh!! Like that's gonna work .Crowd participation is the price you pay for becoming a spectator/public interest sport .If your punters dont want to shout at the players ,that's when you have a problem .Lack of atmosphere is seen as a problem in main line sports.As Kevin says you will have people coaching they're opponents at the top of their voice. In the past ,knowing the field thoroughly has meant teams come prepared knowing the shots n moves and on field comms is probably enough.Now with no fields and no coaching ,it will turn it into more of a lottery than a skill test . F1 has 3 practice sessions ,cricketers net ,and all football teams warm up beforehand . The pro teams will still practice on the "typical " field .But if implemented lower down would hurt paintball fields .