VERY hard to see from the map, but you can.

http://minecraft.xandorus.com:8123/?worldname=playground&map...

See the area in the centre with the red and yellow flowers? In behind the glowstone is the sign. You can catch the edge of it.

I've always suspected this was just an easy way for her to get out of the limelight, to be able to get away from the torrent of tweets, emails, threats, whatever else being in the public eye does. I have no inside information, of course. Just a thought.