Some people do take ball tag a bit too far. Some people treat the ball like an extension of their fist, and a rock hard soccer ball to the back of the head is not fun, well, I assume it isn't, those kids usually don't cry when they're having fun. I heard some guy got knocked out a similar way. Every now and then the teachers' and parents' minds are in the right place and they save some kids a whole lot of grief.
I find it interesting people always talk about how this new generation isn't being brought up right, but it's not like the current generation of adults and teenagers were either. The whole world is in the shit because of people of the past and present. I'd have thought it was obvious that something needs to change, but every adult thinks kids need to be brought up the way they were. Teaching children the things we learned in our childhood means they will grow up to be just like their parents, their parents who are about to push the earth into oblivion. I'm not saying stopping kids from playing harmless games of tag (not ball tag, just normal tag) and testing their strength with a simple arm wrestle is going to create a better generation, but something needs to change, and I'm betting creating an environment where kids are brought up being a lot less hostile to each other (i.e. not smacking each other over the head with soccer balls) is a good start.