This junior thing has been going on forever. The older generation always says, "Ah, look at those young punks with their "whatever" hair and their stupid clothes. They have no respect for themselves or anyone around them.
The fact is, when I was a junior, even though we did the odd stupid thing (young people haven't quite figured out cause and effect yet), for the most part we moved along well, played well, and had pretty good etiquette. It was more likely that the group of men who played EVERY day as a group for money were probably the ones swearing and holding the course with slow play.
The same thing these days. I see WAY more guys in their 20s and early-30s doing stupid things, drinking, acting out, and generally abusing carts. Almost every young kid I've seen and played with has been really good and impressively respectful.
So, I guess my answer is, "Nope, haven't noticed that."
(On a side note, I do notice WAY more young guys in carts nowadays. We never used to take carts, mostly because we didn't want to, but more because we couldn't afford to.)