You used an extreme example so so did I. But really, grounding is practically the kid equivalent of jail.

What if their friends die the day you don't let your kid meet them? They're never going to be able to see them again so you shouldn't ground them in that scenario either. If your kids were going around (potentially) sleeping with older men and constantly disrespecting you I assure you you would not be giving them the birthday present they desired. You're thinking of this as a teenager with stan goggles on, not as a parent who has an out of control teenager.

I'd obviously be pissed if my mother took my tickets away at the time, but she would be completely in the right to in order to stop me getting pregnant (if I were as a female, as in the story) or ending up in real jail. Especially since she had bought them for me, and so they are rightfully her tickets. (The story seems to imply that the tickets had not been given as a gift yet, the mother was simply breaking a promise she made)