It's not just the chanting. It's large (40-50 kids) groups of minimally suoervised teenagers overwhelming attractions and parks. Was at MK on 4th of July, enjoying a late lunch (more like early dinner) at Casey's, watching parade CMs setting up for the evening celebration. And suddenly, a group of 40 or more teenagers, linked arm in arm, chanting and clapping, marched down Main Street. They were three or four abreast, so they took over Main Street. Folks had to get out of the way. Finally, when they reached the Hub, CMs stepped in and made them disperse. Other guests weren't happy. Especially those of us excited about the upcoming celebration of our Independence. They overwhelmed everything on Main Street. The next day, visiting Hollywood Studios, several groups constantly did this. Imagine being at one of the smaller parks, on an already crowded holiday weekend, when three or four of the groups show up. They line jump, ruin many a ride's queue experience. I've stood patiently in line for ice cream at DHS, watching as the 2-3 in front of me suddenly let 10-15 of their friends jump in line. If you say anything, they act like they can't understand English - however, they were able to order their ice cream, in perfect English.
Disney has finally started to control these groups. Don't have a problem with guests showing their excitement at Disney. I DO, though, have an issue with large groups of teenagers acting like this and ruining the experience of other guests. I would be mortified to act like this in another country....