Maybe the camera just couldn't pick up the monofilament fishing line attached to the skyhook that's holding up the EMT in the second to the last pic?? Or is it more of George C's "Invisidorf"?
I love the 2nd to last one with the set-screw connector. It's up there like a neon sign. I guess sometimes the right fitting isn"t on the truck & maybe nobody will see it, but that one is hard to miss.