I assume you're talking about the "Power/Menu" button on the Sansa. It has two labels, Power, and Menu. I suggest we use it as the "Power" button is used on other targets, because there's also a second "Menu" button on the Sansa that serves the purpose of the Menu button on other targets perfectly well. This results in a consistent interface among targets, and the only thing we ignore is that the button had a dual purpose in the original firmware. The menu-only button is the closest match to the "Menu" abstraction, and the "Power/Menu" button is closest to the "Power/Stop" abstraction.
yes, but If what you want to do happens, the power/menu button (which is probably the easiest button on the thing to press) becomes almost never used. I agree that some consistancy should be there, but I dont think that making one target less user friendly for the sake of this is a good idea.