I assume some grey-hat realized the crosswalk computer used a default password and decided the only way the city was likely to fix the problem was this.
"The EPBS will compare the system security code with the code entered on the E-Configurator. If the code matches, you will have an opportunity to change the code. Press NO to continue on without any change. Press YES if you want to change to a new security code at this time. Entering a new code uses the same technique just described, using the Left/Right and Down keys. It is necessary to use a security code different from the default AAAA. Failure to change the code will cause a periodic message to play – “CHANGE PASSWORD”."
they just didn't RTFM and that password is still set to AAAA
This truly is the right way to handle PSK auth. The "UX" for it isn't as nice as some people would like though.
The troll thing to do is set a password if you find one of them in the wild.