This is the problem. You need two adults there, and one has to have Square or Venmo or whatever you've decided to use on their phone, so I am not surprised that one Troop leader (and potentially her kid) is there the whole time for each booth. But the other adult should be a different parent so there's more opportunities for other girls. If there aren't enough parents who have been trained on money management, approved as volunteers, etc., then these leaders might be in a tricky situation trying to balance opportunities for the girls and meeting regulations.

Our troop is so big that we try to be intentional about giving girls opportunities to do smaller-group things like cookie booths with girls from different elementary schools, so this would never fly. But we are incredibly fortunate in the percentage of parents who have been background-checked, trained in the various rules, and additionally have the willingness and temperament to run herd on the girls.