I could say the same thing about standard valve stems -- used them for years on aluminum racing wheels, never had any problems. The only time they didn't work was coming off of a winter glacier run where we crossed flowing water at -20 degrees and totally packed the wheels with ice. But then, the inset stems would not work either because you could not get to them. I have never lost a valve stem in rocks, deep mud, or anywhere else, so I just wondered if they were an answer to a problem that didn't exist, or if perhaps some folks were losing valve stems regularly to debris in the wheel.