I would just take this approach. You miss games or practices you have to sit when you come back. You then have to win your posistion or playing time back. This will put the ball in the players court so to speak. If they really want to play they will not miss. If they really dont care then they wont mind riding the pine. The ones that really want to play you will not have to worry about them missing. And those are the guys you want on the field anyway. Once players see that there will be a price for not coming to practice or games they will start to police it themselves.
For the life of me I can not understand any player that really loves to play having to be forced by rules to come to practices and games. Im sure none of these types of players plan on playing past HS.
How can some guys go four years and never be late one time , never miss one practice or miss one game? Maybe these are the guys that really want to play and understand the importance of team. All the other guys are rec players with rec mentality.
This has just never been an issue with our program. Its hard for me to imagine it.