I live in the northern Chicago suburbs too. I have not used a front license plate on any of my cars for over twenty years (all living here). I have only been stopped twice - once, when the NSX was brand new and the cop just wanted to get a closer look at it, and another time, in the Integra, when the cop seemed like he was just having a bad day. I was not issued a citation on either occasion. Which isn't bad for almost 400K miles of driving.
One thing I do is make sure I keep the second plate in the trunk, just in case I'm asked for it (so they don't think I'm using the plates on two different cars).
Most cops know that people with high-end cars don't like using the front plates, for the looks. It's no big secret.
I figure if I'm ever stopped, I'll plead that I've had it off, lost the frame, blah blah blah... Worst thing that can happen is you get a fix-it ticket (no points) and go plead that you had it mounted...