I have included it a couple of times, most notably in "The Fifth Key". I honestly think that having a basic karaoke system like the one I had would provide for a lot of entertainment well after the event, when there won't be any touring bands, and entertainment in general will be in great demand. There are a lot of talented people everywhere, and even if not, it is still fun. A small genset, a couple small TVs, the karaoke machine, and you're in business. People sit around, take turns singing, entertaining themselves. Either for a small stipend, or as a free draw where profits are made in other ways.
I've not had it as a condition of employment but do consider it a very valuable tool for not only self awareness but interpersonal skills. Fascinating field of study.
No problem. There are also people who recommend putting acetone into your gasoline tank, but I wouldn't bother with that sort of person, either. Good luck on convincing people, though... they have a tendency to disregard fact and to instead cling onto what they FEEL is true.