I've been skinning them like that since my dad showed me in the 70's. It's amazing how hard it is to skin one if you don't know how to do it.
We had a group at our farm in WV last year squirrel hunting...and we had a pile of squirrels. There must have been 30 or 40. It took me about 1/2 hour to skin the whole pile...with someone else gutting them.