I've relieved one in a varsity game. He wanted to stand perpendicular to the sideline and generally got in the way. Once he criticized the BJ for not calling a PF right before halftime, I decided I didn't want to deal with him in the second half so I told him we wouldn't be needing him back and to go watch in the stands.
I canned two dads off the crew in a MS game when they wouldn't pull back to the back of the restricted area. The box man actually told me I was standing in his way so I fixed it for him. Stick man says "you can't talk to him like that" so I sent him off too. He went whining to the AD who told him that "Yes, he really can do that". He then threatened to call the booking agent.
I had a varsity player on JV night kept flirting with a cheerleader to the point he was distracted so I told the coach at halftime I needed a more "mature" box man for the second half. He walked off shaking his head and muttering but sent me a different player".
I've gotten a whiff of booze off a few over the years, especially when it turns cold , but they've been able to perform. My training official fired one once because the box was the only thing holding him up.