Win as a team, lose as a team. If someone's late to practice, you're going to suffer as a team anyways. It's not so bad.
To put it into perspective, when I cheered, my coach and her boyfriend (now fiancé!) heavily did crossfit, and they even now own their own gym...so just imagine what happened to us when someone was late, someone rolled an eye, talked back...you don't want to imagine it. Coaches only want what's best for a team because they want to see you succeed. If conditioning will teach someone to not be late, so be it.