I live in Poland, where we use km as distance units, not miles. When I view my trips and I'm logged in, then I see distance in km, as I set in my profile settings. That's correct. But when my friend views my trip and he's not logged in, he sees distance in miles. I think you should make a change, so that when someone not logged in views a trip, he sees distance in units set in profile of creator of this trip. It seems that now it always defaults to miles.