"Do Not Disturb" Signs

We have decided to give each employee at my workplace the opportunity to keep other office workers from pestering them. I was asked to create a few options for "Do Not Disturb" signs that can be hung on people's doors (or across the doorway of their cubicle). Here are the solutions I have offered to this seemingly boring design problem:

I do so love this font (Corinthia) and am determined to work it into a project here before I leave:


A very office-centric solution:


Someone recently brought a typewriter into the office to 'easily' type addresses on envelopes...only we can't find an ink cartridge for the darn thing. Still, I was inspired:


A solution with threatening overtones:


My favorite option:

We are voting on these options today.