It seems crazy to me that something so minor can have such a big impact upon the medical. Durgs are bad m'kay!
It's difficult not to get on the moral high horse, some may think your actions are no worse than someone drinking alcohol. At one time, I may have thought the same, but recently I have seen a lot of people who appear f8cked up by weed.
But look at it from the AME's perspective-he's not there for the good of your health, he's there for the good of mine.
And, a one off, or not, you've taken a mind altering substance. Why should he take the risk ?
I'm not trying to get too deep into the right and wrongs, I suspect there are some differing cultural perspectives between alcohol and drugs.
Coke tends to be the drug of choice for those prone to drug testing, purely because the half life is shorter, hence staying in your system shorter. (Rife in custodial institutions I'm told).
Don't shoot the messenger
