As @b4n said on #633 it should not be bound by default.
Keybindings can be typed by accident, (like you accidently holding `ctrl` when scrolling, someone accidently holding `ctrl` when typing `m`) and people accidentally hiding their menubar and not knowing how to get it back is a "bad thing" :tm:. Whilst I still think it should have a confirmation dialog, at least if its a user defined key they can be expected to remember it.
Also if its not stolen by the desktop `<Alt>h` `s` will show a list of keybindings for those with faulty ... erm, you know, thingys ... oh yeah memories. But when the menubar is hidden thats also not discoverable.