I'm not advocating violating the CoC in the following remarks. But if one buys two separate tickets, IAD-ORD-MKE and ORD-IAD, and fails to fly the ORD-MKE leg on the first ticket, the odds of any negative result are very, very small. (Of course, there can be no checked bags).
Suppose on the first ticket you got sick at ORD during the connection to MKE and couldn't board the flight -- are they going to fine you for being ill? Or for going to the wrong connecting gate at ORD and missing the flight? Let's be real.