flipchart when I flew Australia - London & back again, my kids were dreams to be honest. They slept most of the way. And dh was at the other side of the plane, so I had the 2 on my own. No, I didn't pay to book seats together, because it doesn't work like that on international flights. We rocked up, said what we needed & got 3 & 1 for the first flight, all the others were 4 together.
Dd2 did throw up, but we caught it in time. She was also restless coming home & didn't sleep well.
I guess I was being somewhat OTT with my descriptions, but dd2 would certainly think it great not to be restricted by her parents.
And what the hell could I honestly be expected to do about it? Would other passengers be happy with me constantly bending over them to attend to her? In reality, she would probably spend the entire time on my lap.
On principal, people should not have to pay extra to sit with their little kids & certainly as linked to below, easyjet won't even let you sit away from 13yr olds, so people paying to sit with their under 13s are being ripped off, in essence.