I think one smart thing they did was put up signs reminding/warning people that the system will make short stops on a somewhat regular basis. That way people aren't getting nervous over the run of the mill 2 minute stops while someone is needing additional load time somewhere along the line.
I also think loading smaller groups is smart. I think it's always just faster to load less people, no matter who they are. And, if there are a few groups who don't know one another, as others said, they may be more moving around to find a balanced, yet comfortable seating arrangement for everyone. Some kids (or even adults) won't want to sit next to someone they don't know, so they'll be taking longer while they try to swap spots, etc.