I am using the Dashr Blue to time flying 10's and 40's on an elevated track in our school facility. Sometimes the system will have a misread resulting in an impossibly fast time. Basically the laser is getting tripped before the runner passes the beam somehow. For the 40, the start laser will sometimes get tripped AFTER the runner leaves, restarting the timer and also resulting in an impossibly fast time.
My theory so far is: Shaking of the track due to the runner or other people on the platform might cause the laser to move enough to think it is being tripped? I didn't think it would be that sensitive, but it is the only thing I can think of. I have not used the system on a track or turf field yet to compare, so that is the next step.