From United’s website:
How can I request a special meal?
We offer special meals on select routes when a breakfast, lunch or dinner is scheduled. A special meal can be requested at the time of booking or by adding a request to an existing reservation.
If special meals are available on a flight, you will be able to make a special meals request during the booking process after signing in to your MileagePlus account. MileagePlus account holders can also add special meal preferences to their profiles for use with bookings made through united.com. When signed in to your MileagePlus account and making a reservation on united.com, if you have a special meal preference set in your profile, you should verify that the correct special meal has been assigned to the applicable traveler’s name prior to confirming the reservation.
If booking outside of united.com, a specific request must be made through the original booking channel for the available special meal to ensure it is included in the reservation, or by contacting the United Customer Contact Center.
I don’t know if you have kids, but can you possibly imagine a special unforeseen situation coming up during a long day of flying with a special needs child. This mom wasn’t asking for a college scholarship for her kid...just throw a meal in the microwave. BTW the most dangerous time for accidents in a plane are during landing and taking off. If the flight attendant accommodated the initial request this could have been avoided. Now we make an unscheduled landing and call the cops in to take a little crying girl off a plane.