If you look at the 24 hour history on the webcam link, it definitely looks like a balloon (not visible in the capture below). The only thing I can think of is some sort of shadow test, since it was up in the late afternoon. Maybe the crane was supposed to represent the planned tower since it was fully extended vertically, and the balloon could have been to add the extra height to reach the equivalent of 16 floors? That's a complete guess.
http://history.novascotiawebcams.com...re/3-16-11.jpg