More funny than dangerous. Did it more than once during the first week or so. Since the ratios are fairly close and you have to go through the gears in sequence there is no way to go from high to low. ( even if you slap it from high to low, the tension on the hub only allows it to go to 2nduntil your cadence catches up and then it will slip into low ) That being said, while spinning along a modest downgrade, preparing to make a turn onto a steep upgrade ( forgetting momentarily what I was doing ) I slipped the hub into 2nd from high. The bike slowes rapidly, you look like a cartoon and everyone including yourself gets a bit of a chuckle. I did this at a much faster speed than I think you would ever do on an upright loop frame.....so no worries....only a few opportunites for comic relief.