re:door buttons. ADA doesn't require them, so US places only put 'em in under pressure. It's another thing to maintain (and keeping the buttons operating in midwestern temperature ranges (100°F -> -40°F) is an engineering challenge (i.e., they break a lot).

and it's weird about zoos, because there are always a significant number of wheeling patrons—in addition to those of us who roll due to impairment, there are strollers stroller strollers strollers strollers strollers strollers.

(also strollers).