I must take exception to these tips.
When ripping against a fence, it is an every day occurrence for your hand to get close to the blade. The keys to safety are to always know where the blade and your fingers are, to never place your hand or fingers in-line with the blade, and to keep several fingers wrapped around the fence (to guide your hand) when ripping stock as narrow as about 1". For narrower stock use a push-stick. For short, narrow stock I use a block of plywood cut to both push and hold down the stock.
When making blade or fence adjustments (something one does very frequently throughout the day) it is perfectly safe to leave the saw plugged in. However when
changing blades it is recommended to unplug (though I don't).
None of my 4 table saws can be turned off with my knee.
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Yeah, you are probably right about the distance, that's why I said maybe. I went conservative because I didn't want to feel guilty about someone getting injured.

I push rips through with my hand but if it gets down to 5' or less out comes the push stick. The thought of ripping a one inch strip with my hand between the blade and fence though gives me the willies. And good point about curling some fingers over the fence.
My saw has similar switch to the one in your photo and in the same spot and I touch it with my thigh or knee to turn it off. It's magnetic so just a touch is all it takes and I don't have to take my hands off the work-piece. I have seen photos of a paddle type board hanging down over the switch to make if easier but I don't have any trouble with out such a board.
Here is another tip I thought of: When pushing a rip with either your hand or a push stick always keep a clockwise torque applied to the board in addition to pushing forward, down and towards the fence. This helps keep the far part of the board against the fence. Kick-back happens when the part of the board that has already passed the blade moves back to the left a little and the teeth of the blade that are rising and moving toward you grabs it and throws it at you.
Adding a little silicone caulk or rubber to the end of your push stick helps it grab the work-piece and able to apply this pressure to the work-piece.
I admit I don't unplug my machine when changing blades and such. But not saying I shouldn't