I'm not sure a case is enough;
If the non-resident leaves leaves his/her vehicle unattended, he or she shall store the firearm within a locked vehicle or locked container within the vehicle in accordance with subsection (b) of Section 65 of the Firearm Concealed Carry Act. It sounds like the case must be locker OR the car must be locked, it seems like a locking case is the only way to avoid any doubt. I'd hate to get out and attempt to lock the vehicle only to be arrested for having a gun in an unlocked car... maybe I'm just too distrustful of IL
Also it seems that you do not have to disclose you are carrying a firearm:
Must Inform Officer Immediately on Contact By Law?
“NO”
(g) A licensee shall possess a license at all times the licensee carries a concealed firearm except:
(h) If an officer of a law enforcement agency initiates an investigative stop, including but not limited to a
traffic stop, of a licensee who is carrying a concealed firearm,
upon the request of the officer the licensee
shall disclose to the officer that he or she is in possession of a concealed firearm under this Act, present the
license upon the request of the officer, and identify the location of the concealed firearm.
That said on I'll make sure my locking case is under my seat, my recorder will be on, and I won't break any traffic laws and if I am stopped I won't bring up the issue... from that point I don't see how an issue could reasonably occur. I never stop in IL anyway I'd rather get to IA or WI and give my money to residents of those states and at locations where I'm able to defend myself.