" Some (of course not I)might say
that if you have been off the drug for a couple of weeks and are not
suffering any ill effects, why even report previous use? It's not like
it's an illegal drug"

Honestly, not reporting the previous use is something that I
considered. (And quickly dismissed).

Ethics aside, I was under the impression that part of the exam was for
you to disclose any and all care providers, who would (be it
theoretical or not) disclose the usage to the AME.

But, regardless, as one who has jumped out of airplanes hundreds of
times, I have learned that the regulations are rarely put into place
arbitrarily. They are there to save my life, and the lives of my
potential passengers, and those below me, as well as to impart a level
of respect and confidence to the public at large.