Shaving dogs fur off

What's the purpose of this? I've seen several dogs while browsing online that have some of their fur shaved off.. mostly it's the ribcage and loin n flank area. Sometimes the neck n tail.
There's one other thread on this site where someone asked but they didn't receive a definite answer. Some suggested it's to make weight. The couple things I can thing of are one, if it's the tail that's shaved, so that folks don't see a bushy tail. The second is perhaps to rub ointment on the dogs body during a rubdown or something along that theory, to help with a keep.