So my friend sent her son (13) to the el cheapo hair salon (within walking distance) with $20 to get his hair cut. He came back with a kewl Beckham-style cut, and with blond streaks (his hair’s light brown).
Friend: :dubious: “How much extra did that cost?”
Son: “I made up the difference with my own money.”
Friend: “…Well, it looks good.”
Grandma: “She didn’t know you were going to do that?”
Son: “I didn’t think of it until I got there. They did highlights on this other guy, and I thought it looked cool, so I asked how much extra, and they did it.”
Grandma: “Well, they should have called and made sure it was okay with your mother! You’re a minor; they can’t do that without a parent’s permission!”
Son: “They didn’t ask.”
Grandma: “Well, YOU should have asked! [to Friend] You would have said no, wouldn’t you?”
Friend: “…I don’t know. Anyway, it’s okay; no harm done.”
Grandma: “No harm done?! That’s going to have to grow out! They shouldn’t have done that without permission! YOU shouldn’t have done that without permission! You couldn’t get a piercing or a tattoo without permission; hair is the same thing! I’m never going to that salon again! I can’t believe you disrespected your mother like that…”
I dunno. Personally, I think Grandma is stuck in the '70s. Blond streaks are pretty low on the scale of outrageous appearance changes. Piercings and tattoos are age-restricted because of the liability issues, but I’ve never heard of an infected highlighting.
Still, it is a change. Not as drastic or politically fraught as getting his head shaved (I think I’d want to know about that, and the motivation behind it), but a change that he made on a whim. So, would you have wanted your kid to call and ask for permission to get blond streaks? Or any other change?

Once he’d seen how it looked and decided he didn’t like it, he went back to his regular once-a-month schedule.