First, don't see the need to point out spelling errors.
Secondly, it's his yard. It doesn't look at all deep, and if you're allowing your children to run all over people's lawns, then it's kind of your own fault.
I could see a fence around a pool, if he had small children around. I don't see the point of a fence around a koi pond that's been outlined in big rocks..
Looks great pigfat. More pictures better be coming once you have fish!