Oh yeah, I forgot about that "intent" ambiguity IL has in its laws.
To be honest, I don't know if the swedge makes it illegal or not. "Dagger" in other states is sometimes classified as a double-edged knife, but other states' definitions don't have any relevence. IL's laws don't define "dagger" or specifically mention double-edged knives. So I'm just guessing. If you're worried about it, I'd just dull the swedge. Except for self-defense purposes, I can't really see that a sharpened swedge really has much use on a carry folder. In fact, I'd be worried that I'd accidentally cut myself on it.