Just curious if maybe pretty much every table saw manual ever got it wrong in the general safety area where they state never to run wood backwards? And what's the gain, you saved 12 seconds? Seriously, if you feel that lucky, just go to Vegas. The risk:reward ratios are much better, there.
You are the only person I've heard use this description ....run the wood backwards. It just isn't what's happening. You make a partial pass, and withdraw the piece in the open kerf that you've just made. You can leave the machine on or turn it off, which ever you choose, it's your choice, what ever you feel safer doing.
Obviously with it off, nothing "can" happen. With it still on something "may" happen, but in my experience, it has not. It's still your choice.
As I mentioned, every time you crosscut with a sled , you withdraw the work or the slde in the kerf made by the blade. I've not seen any online sled videos where a person is making multiple crosscuts who turns the machine off. I don't do it either. It's just not necessary, but it's still your choice.
Every time you make a crosscut on a RAS, the blade is in the kerf in the table or the saw won't cut all the way through. You are constantly moving the blade back and forth in the kerf each time you make a cut. I never turn my RAS off until I'm completely finished cutting all my pieces, especially when making multiples the same length using a stop block.
I not trying to convince you of anything, I'm merely pointing out what I do and why. It's always your choice how you use your saw.