In my experience, ATM receipts are the _most_ accurate.. something about banks being very concerned about the timing of transactions..
Banks have to be all on the same time because money is international and times are key to deposits, money transfers, interest calculations, late fees, etc.
Just about anything that is networked via the internet uses the Network Time Protocol (NTP) which is a standard Internet Protocol (IP) for synchronizing the clocks of computers on a network. NTP was developed at the University of Delaware in 1985. It is one of the oldest internet protocols still in use. The displayed (Local Time) is determined by what time zone offset is selected in the settings of the device.
If the time displayed is off then that device is not connected to the internet or is not setup to automatically set the devices time.
Spotwalla most likely is using NTP and it is an impartial witness. Even if it doesn't use NTP to keep it's time correct, the track displays a continuous timeline from which you can easily determine the duration of the ride.