Then you have been lucky or they found something (spag bol in Y, plated in J and added a kit kat, chips etc). In my experience children's meals have only ever been loaded when requested through MMB (or through a TA). And actually BA are quite good here, as other airlines (e.g. LH group) only let you have a kids meal if you have booked a child's ticket. But the reverse has never happened with any airline thatw hen we booked a child's ticket and did not request that a meal had been loaded.

We normally just leave it to the randoms as some of the kids meals are great, others have been quite dire. And there alwasy seems to be spag bol, chicken rice or similar somewhere on board.