In a caucus, you don’t vote, you stand with a group to show your support.
When Iowa caucus goers walked in to a Decmoccrat caucus room, I would imagine there were a couple O’Malley folks. Because he was getting less than 15%, those people had to pick another camp - in this case, either Hill or Bern.
When everyone is in a camp with over 15%, then counts are taken and delegates for that precinct are decided. In this case, they walked in and because of the t-shirt colors, they knew which camp they were going to be counted with - unless there is a group telling you they are x instead of y...I guess...
Okay but you’re counted, aloud? Theres a precinct captain?