I've always flown First Class, so has DH, DS, DDiL (since joining our family) and now DGS does the same.
We're very aware that as a baby/toddler he could disturb other First Class passengers, so always travel with lots of things to amuse him, and with all four adults to occupy him he's no problem at all.
However, I think Kirsty is completely wrong making the excuse that she doesn't want her boys growing up with a sense of 'entitlement'. Our DS has no sense of entitlement as he is completely aware that we worked very hard for what we have. DGS is also being raised to know that if you want it, you have to work for it.
I honestly don't know why there's such a fuss being made about it anyway, it's not as though Business Class is anything particularly special. I once looked into a Business Class lounge, just for the sake of comparison, I was singularly unimpressed, I'll stick with First Class please!