They do have more gunners per Magrider, but they do not specifically wait for those gunners. Since the stats show they are pulled at similar amounts per player there is a similar amount of planning going into it. The Magrider does get more gunners, in fact they get so many gunners that every Magrider should have one and a small portion of extra gunner in its gunseat all the time. We know that not every Magrider is always gunned and we also know that the only way for Magriders to have more gunners than guns is to have players exit and someone else jump in. Combine those two points, what do you get? Magriders are much more enjoyable to gun for than the other 2 MBT's. The Prowler especially shows a lower amount of gunners due to its main gun stealing kills. So why is the Magrider gunseat so much more attractive? Well there are only two reasons I can think off: it is more powerful and the MBT its based on offers more for gunners than the other two (like enjoyment). Planning and teamwork are out of the question as we would see that back in NS weapon stats.