It actually helps keep the line moving, even if almost imperceptibly so, and just makes it easier to keep track of everything, operationally. Instead of having a group of two or 3 every other dispatch in the front row and not knowing if the empty seat is filled or not (easier to just call for a single rider after you have grouped all the rows if you have time to than for every odd group in a situation like this), you know you have full rows for each dispatch. Once demand dies down and they're not as concerned I'm sure you'll be able to wait for the front. Meanwhile, I'm enjoying them pushing to hit their intervals.