How long was it . . . how did the parent/guardian react? How long do we wait? At some point a decision had to be made, and it was. At that point, it's too late to return, even if Mom sees sense.
You don't board a drunk at LHR
in the hopes that he'll sober up in two hours, he probably won't. Similarly, I assume with due reason, you cannot expect a parent that refuses to secure a child on take off that he/she will do the same on landing in two hours. An unrestricted child is a hazard, believe it or not.
Probably, all probability, this spanned more than 5 mins, but even if not, time is money. I'm sure the crew spoke to the parents/guardians, how they took it is what led the decision. An example was made.
I've seem similar, many, many times . . . most are resolved, timely or untimely. There's always some folks that you can't appease, and seemingly this was once case. Bravo! They won't fly BA
again, so they'll fly Alitalia . . . their safety/situation was obviously different.
Essentially dumb, but a captains call. It happens daily, this one made news because of a child, Italy, BA
and the mention of Vogue.
They'll be others.