If you're in T3, you can exit on departures level through a revolving door (behind the escalators going down to baggage claim) . If you don't want to leave security, you can watch your child walk through to the departures level and see him meet with family. If you go with, you'd be spit out between the various checkpoints.
http://www.flychicago.com/SiteCollec...0-%20PROOF.pdf The Benz logos (ha) are exits on departures level that you can see through.