"The issue of probable cause would be interesting"
There is not sufficient probably cause here. The officer is so deficient he should be terminated along with all those superior to him on duty that day.
That is basically the point I was trying to make. The three of us will roll our eyes upon learning that he was arrested for trying to pay with legitimate currency: two-dollar bills. We will all agree that it doesn't make sense. That being said, when or if, the issue is put to a jury in Maryland, will they believe that the officer, even if mistaken, or downright stupid, has probable cause to arrest? My guess is that they will laugh their asses off in deliberations at the dope, but won't award any money. Well, maybe a couple of thousand dollars.