I've been stirred to 'un lurk'.
Operating a table saw with no guard is unwise, operating one with no Riving Knife is just plain stupid IMO.
I think learning good practice is more important than flimsy plastic guards that'd be plucked off in the event of a kickback.
Here's a nice little video where a guy recorded himself forcing a kickback. I feel the mistake he made was making such a wide cut against the fence, he should've been using a miter guide, a sled, or at least a better kind of push stick(s). A riving knife might've allowed him to get away with the stupid move but I wouldn't recommend relying entirely on it (especially not one on a cheap tablesaw that might be narrower than the blade, not properly set up, or able to flex sideways).
I've never been big on the idea that 'guards lull you into a sense of safety' but sometimes I feel it might be true. If you're operating a tablesaw there's alot to know and be aware for, and alot that can go wrong that a guard won't save you from. I'd recommend reading up on stuff, and also thinking about what'll happen during any cut.
Riving knives might be worth installing for certain types of operations, like ripping beams you suspect might spring during the cut and clamp onto the rear of the blade, or milling damp lumber. But they might get in the way during partial cuts. Also if they're wider or thicker than the blade you're using then they're entirely useless. From what i've seen, the ones that come on cheap tablesaws are just a 'feature' to list on the box and probably not that useful.
I do believe that people not using push sticks are insane though.
