The syrup may have trace amounts of alcohol in it due to the manufacturing process. I'm not sure about Canada Dry specifically, but Coke and Pepsi syrup do:

http://blog.seattlepi.com/hottopics/2012/06/28/coke-pepsi-co... or original article (French) here: http://www.60millions-mag.com/2012/06/27/coca-pepsi-et-autre...