A lot. Ever watched Mike Holmes, or had to go over to someone's home after they buy it, so that you can help them fix stuff, that was not on the inspection? Ours was really through, when we used the Pillar to Post Home Inspector in our town. We though did not know that there was problems with rot on the roof above our entry closet, or along the boards at the edge of the roof, where the gutters are. Because they were unseen items that you could never find without tearing off the roof.
The antenna was mentioned in our inspection, due to CATV was being used, and that the antenna is considered a hazard if it comes loose during a storm. Other than that it was common items like older wiring with no GFCI in the bath or Kitchen, fuse panel which was original to the home. The HI did not find that there was NM buried going out to our garage, nor that there was a hidden splice behind the medicine cabinet in the bath.
So really, I would go through any inspection with the knowledge, that you know more most times, than the idiot claiming to be the inspector. The only inspectors I do not and never suggest arguing with, or building, health & safety, electrical, plumbing, for the city or county. The good thing about the Dearborn COA process, is if you look at their site, they do offer a period that you can correct issues, or "argue" the inspection process if you question items they found, to call them to the table.