Forgive me if I am being dense on this (I am but a lowly student), I have a few questions. Firstly though, I fully understand that a medical is just an indication of your previous health and your health at the medical examination, and absolutely no guarantee that you wont keel over as soon as you walk out of the door no matter how long its validity is.
1) what is the difference between flight instruction and single pilot ops? Ok, for a post solo student then you know that they can land (although they may get lost and it might be bumpy, but generally speaking you'll survive). But for a low hours/pre solo student? From my experience as a student, you progress from being passenger to pilot.
2) at what point does flight instruction become single pilot ops? for instance if you have a "one flies there, one flies back" trip, or if the student brings along a friend? the non-flying person is in the back and so a passenger?