[mnutt]

The same attack is also possible with Flash's fullscreen; their "Press Esc to exit Fullscreen" message would work fine here too.

[sil3ntmac]

I don't think so... isn't the keyboard disabled in Flash fullscreen? Same goes for Silverlight and Java applets.

[trampsymphony]

The keyboard remains active in Flash fullscreen, though you cannot bind anything to the "ESC" key if I'm remembering correctly.