I just want to clarify a few things:

1) Asking isn't at all unreasonable.

2) It isn't the asking that shows an sense of entitlement it's the idea that people should say "yes" when asked and the feeling of disbelief/anger/ignominy that's generated when a "no" is received.

3) When I see hyperbole being used to describe the effect of a child being separated from his/her parents on a plane ("traumatic" etc..) and then see that the reason the child is separated is because the parents wouldn't pay to prevent said "trauma" my sympathies evaporate rather quickly.

4) Further to the point above, it also diminishes my sympathies considerably when the reason for the "trauma" is because the parents knowingly chose a flight where sitting together was not an option at the time of booking (when in most cases advance planning is possible but just wasn't done)

It all comes down to this: If you're not going to help yourself please don't expect others to go out of their way to help you.

p.s yes I know there are exceptions where parents need to fly with their kids at short notice. Nothing I've typed refers to those situations.