I've comment on this before. I don't think it ever wise, and particularly stupid at the varsity level. At other levels various degrees of "emergencies" happen. In my first or second year I became the emergency referee for a JV game my son was playing in. (Actually, he mostly played the bench, but no matter.) It was tied after 1, tied at half, tied after 3, and on a controversial call by me in the last 2-3 minutes our team (visitors) got 2 shots and held off to win by ~5. Ugly.
This year I ref'd one of my daughter's 8th grade games. The alternative was for them to have only one official. It was no big deal. I will probably ref every one of my daughter's games this year in the church league I help run.
My opinion on officiating games below varsity are:
- make sure both coaches know and agree, and
- work at a level below your skill (e.g., varsity-capable official doing MS is not likely a problem at all).