Remember.. the ADA doesn't provide you "equal access" or "equal experience" - It's meant to ensure you aren't --excluded or discriminated against--. It is intended to ensure you get --participation-- without being discriminated against.
The ADA isn't there to elevate someone's abilities... or make their constraints disappear from how they function. It's simply intended to ensure people aren't being systematically excluded or to make reasonable changes so that people can participate without being second class. Example: If someone has limited stamina, the ADA doesn't say you should have provide them with a ECV so they can do more. It says you should allow an ECV that someone needed. This is an important distinction. Just like someone with limited stamina isn't given line skips just so they can experience the same number of attractions as someone else. They would be given line skipping accommodations because they can't function within the constraints of the queing itself.
When it comes to how someone likes to travel (as a group or whatever) you're no longer talking about what someone needs for participation, but just preferences and guest satisfaction. It's within reason to limit someone's ability to function as a single group, especially when that request has operational consequences.
