Ah, yes, the “Miracle Flight”. Where people “Need” a wheelchair to get to the gate so that they can be first on the plane (and take advantage of pre-boarding), but since you’ll be the last ones OFF the plane, they’ll be well enough to get off on their own.
Seen this way too many times.
Okay, I was trying to stay out of this but I can't anymore.
First of all, unless we're talking about aisle chairs (which very, very few people use), folks with wheelchairs aren't the last off a plane. At most airports, the long line of pushers are on the jetway towards the beginning of deplaning. Even I, who have to wait for my chair to come up from under the plane, am almost never the last one off. Usually about halfway through deplaning, actually. So no, that's not really a factor.
But second and more importantly, you have no idea what a person's needs are by looking at them. None at all. A person may be able to walk on their own but not quickly, so they request a wheelchair to get to their gate (when time is a factor) but don't use it to get off the plane because they can take their time. They may be able to walk just fine but can't stand safely - such as in line at TSA or at the gate. Maybe they have a condition that flares up so they requested assistance when they booked their tickets (instead of the day of, because that's what you have to do if you want it guaranteed) but are having a good, non-flaring day when they actually arrive at the airport and therefore can walk back to get what they need. In the case of the two people with chairs where one walked back down the terminal: do you know how fast the pushers go and how hard it is to keep up with them if you're the ambulatory partner? I have watched my partner half-sprinting down the concourse with all our luggage because the pusher just took off to the gate with me in tow but without him. If he had difficulty walking, he might well request assistance rather than hurting himself to keep up. Ambulatory wheelchair users exist, and we get really tired of people either claiming we're faking it or making "miracle!" jokes.
Moreover: given the number of people on this board who do not need accommodations, mobility devices, or other assistance in their daily lives but need it at Disney parks, you really don't get to judge those same forms of assistance at an airport. Why do people need this help at Disney but not at home? Because a day at the parks isn't like being at home: it's a lot hotter, further to walk, longer on your feet, more noise, more crowds, different foods, less control, less routine, etc. All of those factors apply to airports as well. So kindly keep your eyes on your own yoga mat and stop assuming that you know why a person needs accommodations - or doesn't.