And I dont see why you think an issue caused by the airlines is parents being a) cheap b) disorganised or c) overbearing helicopter parents
I also just cant agree with this automatic "me" mentality when the best defense you have for wanting the seat is "because I paid for it" even when someone else did and has an actual need for it
As a fellow parent, let me tell you how we handled a situation--which is how I feel parents SHOULD handle it:
Flying from LAX to DET in October 2001 with a two and a half year old and a four and a half year old. We had done everything we needed to do long ahead of time to have reserved seats 2 and 2 so each of us adults could sit with a child.
DS (2 at the time) split his head open when he leaned back in his chair at the gate and it turned out the back was broken and he fell into the support bar below. We missed our booked flight while at the ER where he was got several staples and was checked for a concussion. Our luggage made the flight without us, and the gift shops were closed when we returned to teh airport--so DH and I as well as DS all had blood on our clothes and DS had a big bandage on his head plus hospital paperwork.
We had been rebooked on the last flight of the evening--which was totally full. We were in 4 separate seats scattered about the plane. I had doctor's instructions to awaken DS every 45 minutes that night. (and permission to fly)
SO many people were trying to sit together that the gate agents were making announcements as we got there that they could not change anyone's seat assignments, sorry.
We went up to the agent anyway (BEFORE boarding that flight) and explained the situation calmly, showed them the paperwork from the hospital, etc and asked if it was possible to find a way to seat me with my DS or if we should rebook for a flight going out the next day. Fortunately, a couple sitting near the counter overheard, had seats together and offered to switch with DS and I under the circumstances which were clearly out of the norm and there was a real need. I must have thanked them about a million times lol
DD4 sat on her own a few rows from DH--in the seats they were given when we moved to the flight. She was capable.
Had we not been able to work something out prior to boarding we would have asked to be rebooked on the next available flight which had seats together which could be assigned to us. It would have sucked because DH had to get back to work, so he probably would have gone without me and I would have overnighted in a strange city alone with two kids and no luggage and needing to care for DS'S injury---but that is a risk we take when we travel -- we risk having circumstances beyond our control strand us wherever we are until things settle down. We risk having to wait for flights if they are cancelled, missed or there are other issues which prevent us from flying as planned (like needing to wait for seats together). Responsible travelers assume those risks and do not demand to be exempted from them because they choose to travel with children.
(which doesn't mean I, or others might not switch with someone, just that no one should ever be expected to)