Just expanding on math's reply:
* you can move the "fake queen" and it remains looking like a queen.
* fake queen is a princess but does not extend your sonar by 50%
* Other players will be able to view your hires on the fake queen.
* The "fake queen" can not hire any specs. (So two queens in two locations; hires default to the real-queen location)
So it's only a good trick if you hide both your queen in the fog of war, and then nobody but you know which is the real queen... until you hire something.
Imho it's a novelty act to pull on noobs for shock and awe, but in practical terms I'd prefer a princess extending my sonar. Or three princesses and a sentry.
"I work for the company. But don't let that fool you, I'm really an okay guy."