The John Denver story is an old one - I first heard it from a Bethelite in about 1985, who claimed that she was actually at the concert.
I was at the Vancouver convention when the Glen Campbell story went around, too. I seem to recall someone afterwards discovered that there was a person on the baptism list with that name, but it wasn't "the" Glen Campbell, of course.
There was a bizarre story going around during the Malawi days. We had done this major letter-writing campaign. The rumour then came back that the high bishop who had been responsible for ordering the abuse of the witnesses who would not buy a membership card had been arrested as a result of our letters and had been seen chained to a wall in the prison.