both of our boys are sensitive to the concept of "privacy" when using the restroom.
i believe that this will serve them well in life.
in ben's case, it typically entails a shut door, an adult standing on the other side of said shut door, and him screaming for appointed adult if he needs them.
on one of the days we were in california, i walked into the restroom.
ben came running in with me, spun around to shut the door, and locked it.
he looked back at me with a huge grin.
"i locked it mommy! so no one will sneak in an take your privacy."
(but, also, no thanks.)