Either do SDC (if available) or else visit the friend at another time.

It is downright foolhardy to play games with hub-to-hub flights, especially during a peak travel season. A IAH-CLE flight that appears wide open at the outset can suddenly become completely full by the afternoon as the usual vagaries of weather and ATC take their toll throughout the day, and pax are reaccomodated on those flights to get to their final destinations, to say nothing of the must-ride deadheading flight crews who often take some seats on hub-to-hubs on short notice to crew flights at the other hub.