Well, I tend to think OP probably has a good sense of why baby was crying..............that said, however, many people have posted that ALL the crying/screaming kids they see are tired, hot, hungry or cold and the parents need to take them back to the hotel..........that I disagree with. My kids cry. My 9 year old gets his feelings hurt........likely if you saw him crying it would be because he walked in front of someone and they scolded him, or he missed his turn at a character, or he dropped his ice cream. My 2 year old is a 2 year old. He's liable to melt down over nearly anything.............he doesn't want to be in the stroller, or he doesn't want to hold a hand, or he doesn't want to go in that store, or he does want to go in that store.............on and on ad infinitum. He does his "meltdowns" all the time, even when well rested, well fed, and clothed appropriately for the weather. Going back to the hotel won't help him, and in fact, he'd probably scream more, and then our hotel neighbors would wonder why we couldn't take him out of the hotel so they didn't have to hear him. Some people have expressed the thought that children of this age aren't "old enough" for a trip like this. He would do the same at home................and I see many benefits for him on the trip.......but that could be debated forever....suffice it to say, we think it's good for him to go and he enjoys it, and the rest of us do too!
Again, I do think OP's baby was likely tired or overstimulated, but not all crying kids you see need a nap.