Flushing sound

Today I happened to see a button attached to one of the Japanese toilets that said flushing sound. I kind of got a chuckle out of this and wondered why they would a flushing sound button. Is it for when you are taking a long time and someone is waiting for you, so you can make them think you are farther along in the process than you are. Or is a button for kids to trick their parents into thinking they've gone potty so they can hop off the toilet. (Maybe what they should put is a button that says: its going to be a while, come back later or an electronic clock on the outside that displays how many more minutes you think you will be)
 
You may be thinking that the button is there because the toilets make no noise, but you'd be wrong. They make the same noise every other toilet I've had the pleasure of using makes. These aren't hybrid models that are super quite and you cant hear them when they are on, these are real live porcelain thrones that make as much noise as every other one.
If you can think of a good reason for this button leave a comment and let me know.