I have to confess at being one of the jokers that removed both (and voted in the poll), but my excuse is more to do with the tablesaw being a bit crap in the first place than any lack of safety on my part.
I always stand to one side (never in front of what could be thrown back), and as John alluded to, I find I treat it with a great deal more care and respect with the guard off.
The reason I removed it is because the saw came with what I can only describe as appalling guard/riving knife/anti-kickback system which are all combined. i.e. you can't take the anti-kickback device off without removing the guard and the riving knife.
It's the anti-kickback system that's caused me all the grief, because unless you very carefully align it, I found that 9 times out of 10 the leading edge of the out-fed material would get caught on it as you pushed the material through. This stops you in your tracks, and then you only have a couple of options:
- remove the work, re-align the guard system and then try again
- try to force it through
Neither satisfactory (and not very safe in my opinion), and in both cases the cut ends up ruined. The guard alignment gets knocked out very easily.
As a result I only use the tablesaw rarely (mostly use the bandsaw now). If I had a bigger workshop I'd chuck the flaming thing and buy a new (better) one....