Disclaimer: I am not promoting carrying in IL or Chicago for that matter. I am simply posting my experience for the enjoyment of others...
Had to go to Chicago today with the girlfriend, I oc'ed to the gas station, where someone asked me "Is that real" I replied "Yes." She mutters "puuuuuud." This was before crossing into Illinois
We had to travel through a couple rough patches so I cc through the and down town in the loop. I was cc'ing, not one person gave a weird look, no police encounters, nothing of any type. I walked around in excess of 2 hours.
I carry a S&W Sigma 9mm, so its not a 'pocket gun', I carried in a IWB holster.
I would not have done this withy anyone else, my girlfriend was aware of my carrying.