Upload & Sell: On
After two rolls slipped on me, I always make sure to apply light pressure to the takeup spool and the accumulating paper. Also I have to make sure the paper's rolled diameter on the takeup spool is fully "compacted" otherwise the gathered film and paper backing end up with a diameter that is greater than that of the spool and suddenly you notice it upon opening the swing back. By then, it's too late as if I can see the halides, the halides can see me.
Until I became confident about proper spool loading on the Fuji, I always placed it in a dark bag when removing film. The deliberate way one shoots with a big 6x9 means losing those shots is (was) a serious disappointment. :-(
This slippage never happened to me on Mamiya rangefinders, for whatever reason.