N2P,
I'm not a power instructor, but I have done a fair bit of glider instructing, most of it well before the GoPro days. I have to say I would not want a student recording his flight on video, for all of the valid reasons mentioned here. This thread has prompted me to raise the topic of in-flight video recording with my club's instructors.
With regard to the video of the Cirrus aborted takeoff, I would suggest the lesson to be learned from that has nothing to do with the pilot's reaction time, which was understandable, given that the oil pressure was only slightly in the yellow - I probably would have continued. The airmanship lesson is that he should have made a call to ATC much sooner, rather than waiting until nearly at the end of the runway. Also, the call is "stopping", not "aborting", at least in all the countries that I fly in.