I watched a trad cleaner the other day cleaning a window over a conservatory by splitting his ladder and hooking one half over the pointed plastic decoration on the apex of the con roof. He then climbed up to the edge of the con roof with the other half, climbed onto the half that was layed on the con roof and walked up it to the window steadying himself with his hands on the wall. Scared me silly just watching him. It supprises me that the custy was happy for him to do it.
As for windows over porches, I used to use an extn pole with my trad tools attached. If I felt the slightest bit at risk I would leave it out and explain the safety issue to the custy. If they made an issue over it I'd drop them. It's not worth risking your neck for the sake of cleaning a two or three feet square piece of glass.
I took what I considered to be a small risk once and it cost me a severely broken ankle. It could have been worse. I'm grateful it wasn't.