There's a reason Singapore is home to the World Toilet Organization [1] -- they're really on top of the game when it comes to accepting and embracing the realities of the human rear end. To wit:
"The Restroom Association (Singapore) will be submitting a proposal to the Singapore Tourism Board for a map of key public toilets on the island [2]. First up will be some 500 loos in the shopping belt, with special note of facilities such as wheelchair access or diaper-changing stations.
"And hopefully, said association president Jack Sim, getting marked as a "happy toilet" on the map will be incentive for toilet managers to keep them clean. Filthy loos are apparently one of the "transient" causes of incontinence as people would rather hold it in than use a dirty toilet."
Good for them! And good for Singapore poopers! This is something every city should do -- and not just for tourist, either. There should be a list of public toilets in every city's Yellow Pages or something... because emergencies don't only hit tourists.
Although if Starbucks keeps proliferating like it does, it's a moot point. NYC was a much more unfriendly place for poopers five years ago, before there was a coffee shop on every corner.