Returning to the OP's sentiment over the issue:
As you can see there has been various experiences from other guests and no firm set (or at least followed) rules and thus you might have a different encounter each time. I don't think taking anything on this forum as concrete rules and then expecting them to be accurate will be helpful. Heck, I would even say if there was something on Disney's website about the rules (or ADA rules) and printing them out and then forcing your rights while in the park isn't going to be productive at all. At most, what I would do is go with the flow, and when necessary ask for an exception or accommodation and be thankful for what I do receive. If I feel like I wasn't accommodated appropriately, I would not hesitate to make it known later at City Hall or written correspondence. But the last thing you should be doing is fuming for the rest of your trip over how unfairly you were treated. But, I have always found them friendly and helpful.
I went to DLR's site for info on the Baby Care Center
http://disneyland.disney.go.com/plan/guest-services/baby-center-lost-children/
where there are also links on the left-hand side for people with [certain kinds of] disabilities, a link about the First Aid center, and Guest Relations.
None of these pages had any of the information you need or even related enough to jive with what others have posted as their experiences. Unfortunately, I think
tiggerjay has the most accurate idea in that a lot is not set in stone, which can work for you or against you, and a lot is left to the interpretation, enforcement, and/or accommodation of the CM with whom you end up dealing.
This is unfortunate in that it can lead to what, to me, was an unreasonable and rude experience that you had with your son, regardless of his height, his age, his behavior, whether or not he has a disability, and whether or not that disability is "visible." What you describe is bad customer service, period. No explanation, no posted rules that would disqualify you, and, worst of all, no kindly suggestion of alternative facilities to accommodate your particular needs. You should not have to read on a non-Disney message board about how larger, non-infant individuals can be changed in the First Aid center. That should be something DLR has on their site to help people prepare for their trip. And it's the kind opf detail that really should be something CMs--especially ones monitoring bathrooms and similar facilities for guests' private, personal needs--should know about and help guests out with, starting with the basic concept that guests might have special needs that won't be obvious to the CM with just a glance, so they should ask what might be needed and see how they can help.
Ultimately, just as people have found about less personal issues, like when I read up on people's successes and/or failures in upgrading six-day Parkhopper tickets to seven- or eight-day ones at different places in DLR, if you get an answer you don't like or doesn't match others' experiences, find someone else to ask. It takes energy and time and doesn't make me happy to have as a suggestion for the OP and others with similar questions about how their family will cope with bathroom or breastfeeding issues, but that seems to be the reality.
AJ
