I'd be there asking... "WHY" ? I don't clip whiskers... I use those little dollar things that do it without the clippers. My first line of tidying up our horses is to use scissors first, and clippers last! I have no clue why someone would do it. I work as a foal sitter, and of all the babies I've seen... no one has done this.
I'd go find the guy and ask what he was talking about. Does he live in my neighborhood? We have 29 horse owners around here, and not one of them will agree with another one, about anything.... and of course, every single one is an expert!
God Bless,
Lynn W