My question to my dad was answered:
Hi. Rick, I don't have any facts about the lawn mower story. That story made the rounds when Consumer Product Safety Commission was making all the rules on about every product imaginable, around 73-74. Some so called safety rules were ridiculous or self evident, and the lawn mower story was one used by opponents of the myriad of new rules. The thrust of the story was, "is a rule against using a lawn mower to trim a hedge really needed? ( not that there was such a rule in the works, just an example of ridiculous rules) The story was supposed to be actually true, that a guy used his mower to trim his hedges and lost a couple fingers. We never had any verification of the story, since it wasn't our bailiwick.