ad d’lo yada is a nebulous term. It might simply mean that one is more loopy than usual. As I said my Rov says it is sufficient to be buzzed or feeling sleepy. If you would have a person sit in front of a driving simulator after two drinks, they would probably fail the simulated test, as their reaction time would be skewed, along with their judgment. THAT is what ad d’lo yada implies. Too many people use that “mitzvah” as an excuse to get stoned. Would that they were as dedicated to the observance of the mitzvos of honesty and chessed.
