Strollers are definitely a necessity at MK if you have kids. It bothers me when people complain about strollers, kids running around, etc at Disney. MK for the most part was created for kids, so adult visitors should realize that and just relax. I do, however, believe that those with kids/strollers should be courteous to those around them. For instance, we bring our own stroller on the buses, but I always make a point to head to the back of the bus and stay out of others' way. I don't like being run into or blocked by a stroller either, but you have to allow them at Disney because of all of the kids.