This is just my opinion. I have never punished a kid for anything a parent has done or said. Why would you? The player plays for you not the parent. When you have tryouts to select a team your picking the players based on who is the best players for your team. Your not cutting kids because they might transfer. Your not cutting kids because you dont like the parents or someone said something or did something or might do something. Your cutting the players you dont believe can help your program based on lack of ability to help your program.
A team is only that team one year. Every year its a new team. If you start cutting players because someone might transfer , or you heard someone might transfer or you hear a rumor that someone said something etc your using the cuts for something they are not for. Tryouts are used to select the best players for your team that year. They are not imo used to cull potential transfers from your program. Its based on ability.
Maybe there are some other issues at play here? Maybe the kid is caught in a situation he has no control over? In any case if he trys out and he is deserves to make the team he should make the team. Holding a grudge against a kid and cutting him because he may not be back the next year is wrong imo. Your penalizing the kid for something he might do. Your cutting him because he may not be back the next year. Your cutting him because he may want to go play at another school and attend another school where he has friends the next year. I dont think thats what cuts are designed for and I think it sends the wrong message.
You have no idea who will be back. Who will decide not to play next season. Who will move out of the district. Etc etc. If you start cutting kids for reasons outside of ability to help your team you open up a can of worms you might not be able to put the lid on. And quite honestly your punishing a kid for something he should not be punished for. And maybe he has a great time and enjoys being in your program and decides he is where he needs to be.
JMO