You would think that the insaller would re-use existing poles and dishes if available and in good conditon. In the orignal post , the person complained that in the house next door with two apartments, had 9 dishes attached to the outside of the bldg. That's just plain dumb. At the very least, the pole mount could of been re-used and most likley the entire hardware setup.
Depending on the slope of your roof, it's quite possible to put a dish on the north side of the roof of a south-facing house, as long as the angle of the roof pitch is less than the 30 or so degrees that the dish has to point to to reach the satellites. The dish is basically facing "backwards" from the perspective of the roof pitch but it harder to see. Doing this it's not visible from the ground from the front of the house.