The most public bare spanking I got was in the locker room of a pool club my family was a part of.
I've shared this in another topic before but I'll put it here too.
I got in trouble multiple times for going in the big pool without supervision. I was around 12 years old maybe and loved the big pool but wasn't allowed in that one without a parent with me (I wasn't a very good swimmer)
Got caught a few times and warned.
Guess I pressed my luck one to many times and dad was in a bad mood because this time he scolded me and demanded that I get out of the pool. As I get out he grabs me by the arm and smacks my butt telling me he is tired of me not listening. Pulls me by the arm to the men's locker room.
In the change area with all the benches and stuff he yanks down my bathing suit to my knees (it was all I was wearing so I am basically naked at this point) and starts spanking me right there in the open locker room. There are about a dozen or so people in there getting changed. Dad's and sons. And there's me standing there almost naked getting my butt beat.
I was struggling, crying, probably putting on a good show. It was so embarrassing. After about 10-20 smacks I was told to pull my bathing suit up and I was done with the pool for the rest of that day and I was to just sit at our chairs/towels until it was time to go home.
It was very embarrassing to get spanked and exposed to all those people. They had a clear view of everything amd I of course wasn't really paying attention to who was there. So while back outside, I knew a handful of people had just seen me naked getting spanked but I didn't know who.
That was the most public one I ever got. There were a few others at friends or family houses that I was threatened with a spanking. An occasion or 2 when I was brought to different room. And a few at home in front of others besides immediate family but that was the most public.