Boomer, I think it's great when people can and do stand up for themselves, but we've got to admit not everyone is capable of doing that.
We tell people to play dead when they encounter a bear or cougar... but it's beyond comprehension to expect every kid to be able to stand up to one bully, never mind a group of pricks.
I always told my kids to take the first punch and then fight like hell, but we've got some irish blood, don't piss us off... other kids aren't so lucky.. lol
By the by, this isn't really directed at you, more as to the question.
Just saying, I've known a ton of kids that no matter the training, they would never have been able to defend themselves verbally or physically. Violence should never be tolerated. Sadly it is.
It's time for a hard reality check.. until shite like the housewives, or other mean reality shows and the like are given the heave ho... it's acutely obvious our society admires jerks. If adults can't prove they're above this behavior kids aren't going to change. Guns and violence have way too much pull and kids mirror that. Plain and simple.