Originally Posted by TwoBits
I would not list it, as long as it fits under category #3 that you posted in your original post. Worst case scenario: you get accepted, and after the CBC is released to the school, they ask you about it and ask you why you didn't mention it in your AMCAS. You explain the situation and how you learned from it, and then go on to explain that the probation was completed, and the case was dismissed, which is why you did not mention it since it clearly states not to do so in the AMCAS instructions. ADCOMs have much more important things to pay mind to compared to a misdemeanor for underage drinking.
I think this is too minor to draw attention to it. Yet, ADCOMs might put your app in a separate pile without even reading your explanation, simply because you checked yes, leaving you at a disadvantage for no reason. Say no now (because you legitimately have reason to), and explain later (if you even have to). Just my two cents.
Many schools have specifically stated to me that it's not the misdemeanor that draws attention but rather the fact that an applicant didn't report it. One actually stated by not fully disclosing,"It shows moral turpitude which is not welcome in the field of medicine". OP, I would be very careful about such advice that states not to report a misdemeanor. There was a guy on SDN who got his acceptance rescinded for not reporting a misdemeanor speeding (reckless driving) ticket. I myself had a misdemeanor but fully reported it and had absolutely no problem getting accepted, matter of fact my interviewers didn't even ask so I would urge you report it for your own sake.