It will be interesting to hear:
1) how the cheese sauce was spilled onto the son's face
2) did they report anything at the time, and was it recorded, if the did
3) who was handling the cheese sauce at the time it was spilled
4) did the parents seek immediate medical attention, and what was done
I can't imagine a kid being in a stroller and a parent giving the kid an open container of what had to been obviously extremely hot cheese sauce. If the parents had it in their hands and handed it off, they had to know it was very hot. I can't imagine a server giving a small child a container of anything hot.
Was he trying to play or drink it, burnt his tongue and knocked it onto his face?

Wondering if the parents were letting the 4 year old dispense cheese sauce by himself at a condiment counter.

Was the kid holding his face under the cheese dispenser? But even with that, someone taller would have to be pumping the sauce out. I would not think a 4 year old is tall or strong enough to do that.
I could see new rules in place where no child can be unattended. But betting the parents were right there, if this was the case.
Certainly feel for the kids and the parents. But I would have to hear some swaying information to think Disney is at fault for having hot cheese.