Don't tell someone that you run into on a hiking trail that they are "wearing the wrong shoes for this kind of trail." Unless you have $90 that you'd like to give her for the high tech, over-hyped hiking boots you would find appropriate for "this kind of trail." Or unless you DO feel like getting popped in the nose with a very strong, albeit slippery, sole of a tennis shoe.
Filter it, dude. You'll get there.