What security issues may have when Silverlight App in full screen mode?

In http://msdn.microsoft.com/en-us/library/cc189023(v=vs.95).aspx , What security issues may have if NOT disable events below?

When a Silverlight-based a开发者_开发知识库pplication is in full-screen mode, most keyboard events are disabled. This limitation of keyboard input during full-screen mode is a security feature, and is intended to minimize the possibility of unintended information being entered by a user. In full-screen mode, the only input allowed is through the following keys:

UP ARROW

DOWN ARROW

LEFT ARROW

RIGHT ARROW

SPACEBAR

TAB

PAGE UP

PAGE DOWN

HOME

END

ENTER

One of the things you could do when running full screen is spoofing (immitating) a (windows) log-in box to gather user names and passwords.

By disabling all other keys (other than the ones listed) even when the log-in UI is spoofed the user will not be able to enter his credentials.

EDIT

BTW: you do not need to disable the listed events/keys because there are hardly any security issues involved with these keys. If there is such an issue chances are you will need to disable the mouse too because these keys are very comparable to what can be done by using the mouse.