I have an Android phone and use the Google app "My Tracks" to record walks I go on. Sometimes the rate that it tells me I'm walking jumps wildly high, even though I walk at a very constant rate. Sometimes it's 2x what it really is.

I would hate to be a good driver and be penalized for bad software/hardware. Given the track record of the auto companies (on which the insurance companies will rely), I think it's a given the software will be really shitty.