Funny you should mention that.
That's how I handled my scout troop years ago. ( I was one of MANY troop leaders - just helping out while my son was a member )
When we were on a camping trip, and the boys got into some "colorful" language ... I made them write a letter, using the offensive words, and address it to their Mom's. Then, I held the letter till the second offense, and told them that I would mail the letter if I hear "it" again.

I never had to mail a letter !