emotionally, and even spiritually >>>
only when the parents stay home.
Actually, the reason I used the cursing example is that I have first hand experience of families making changes in their homes when one of their boys is on our team.
I don't stop my players from talking trash at the other team, with the one caveat that they must never curse, and NEVER take the Lord's name in vain.
To be honest, some of the boys have an easier time of this than their mothers. I was continually benching one of our star players for taking the Lord's name. His parents were no better. The mother complained to me. I told her it was a Catholic League and we couldn't have it there and it really didn't matter what she allowed in her own house. Well, to make a long story short, cursing is now forbidden in that house. The mother eventually ended up thanking me for the more civil tone in her home.
Honestly, most parents appreciate rules and are happy to abide by them if they know them in advance.