What about reflections and GPS?
I'm glad you brought up this topic.
GPS locations can be degraded if reflected signals are processed as if they were direct signals, because such signals have a longer path-length and travel time, but are assumed to travel directly from the satellite(s). If the unit cannot remove reflections based on polarization of the signal, an inaccuracy may result.
If you carry the GPS on your shoulder, and there is an extremely dense mass nearby, reflections can be a serious problem. So definitely, some people should not use GPS.
You're welcome, or as they say in P&P, "your welcome".