I managed to foul up 2 trainings on one day. Once by accidentally pressing the start/stop button when I bent over to get something out of my wheel and once by starting a training when the program had not connected to my (serial) gps.
So my 'idea' is integrating an, optional, warning when moving distances (>100 meters??) without recording a training and making it impossible or at least give a warning when you start a training without a gps connection.