Admittedly it has gotten a little off topic, but relevant (and interesting) all the same.
Anyway, I would think that the points of proof would be along the lines of:
1. Identity
2. Did act as a member of the operating crew, (or performed duties and functions prepatory to acting as a member of the operating crew),
3.Of an aircraft
3. And did during the period of 8 hours immediately preceeding the departure of the aircraft
4. Consume alcoholic liquor.
The Oxford Dictionary defines "Departure" as the act of leaving, especially to start a journey.
Perhaps this is why the saying is "bottle to throttle" , not "bottle to sign on" or "bottle to walk around".
BTW, I am not advocating in the least that this should be done, just pointing out ANOTHER interpretation of the regulation.
Maybe this reg. is the thing that is obtuse, ... or perhaps it is just simply badly written..
