^ This will depend greatly on the ratio or amount of sugar to water you have in the syrup. The more water a liquid has, the more likely it is to expand. Due to the formation of large ice crystals that form when slow freezing (which is what will happen in all home freezing cases, unless you have a rapid chiller) the space needed actually increases. Any one who has overfilled a water bottle and then frozen it will know this.
If you have enough sugar or salt in your liquid it will cause it not to freeze.
Snowy, you have caused to me to open my Food Chemistry up and refresh on why some water-solute solutions behave differently when freezing and don't always expand.
Sugar can cause tighter hydrogen-hydrogen bonding than with normal water-water bonds. This is the reason some syrups may shrink. (Least scientific explanation)
Nifty link I found for freezing fruits:
http://www.ext.colostate.edu/pubs/foodnut/09331.html