We're moving our annual trip back a few weeks to August because we were so irritated by the rudeness of these large groups we encountered the last two Julys. I expect to see some of these groups in August, but from what I can tell, July is the peak month for their travels, so I hope I see fewer of them than we did the last two years.
I'm not saying all Brazilians are rude. What I am saying is that large groups of 50 or more teens away from home are not going to be polite if they are not required to be polite by their guides or chaperones. They will block access to rides. They do chant. I have seen members of these groups push others out of the way (including a little girl in front of me) and then pretend not to understand when someone calls them on it.
We had three different CMs comment to us about the rudeness of these groups. One advised me and my DD and another parent with small children to "be careful or they'll run you over" when we were getting ready to enter the Little Mermaid show at DHS. One, our waiter at a restaurant in one of the parks, was from Brazil, and he told us that he did not like to wear his nametag identifying him as being from Rio because he was so embarrassed by the tour groups in the parks in July. He was horrified, and I doubt he was being biased against South Americans in general as he was South American!
I'm SO not prejudiced, and I've traveled all over the world and lived with families in Germany and Slovakia and as a student in France. Please--I know about different cultures and am very adaptable to these differences.
But, these groups are often obnoxious. It could be cultural, as I do know that certain cultures push more than others (go to a bank in England and then one in France and you'll see a huge difference in queues!). It could be social class, as I assume most of these kids are in the upper half or quarter of Brazilian society and therefore have a bit of money and might look down on some of the workers. It could be age related as most teens no matter where they're from do not always practice the best of manners when they are abroad and away from their parents at the same time.
But, really, they do cause problems for the average folks touring the parks, and only those of us who've lived through July can understand it.