I've never cut a filter, but do oil analysis on every oil change. Trends there are what is important. If I were to cut a filter and be able find metal, I'd stop flying that engine immediately.
My wife and I did this cross country last summer, went to the monthly fly-in breakfast @ 4M1, then flew over to 17A and camped Saturday night. Pic is from Sunday morning.
We're riding the bus back from a movie @ the fly-in theater one night. Guy waves the bus down in Scholler. He literally needed to know where he was @. Said he'd be wandering around for a couple of hours and couldn't find his way out.