I would not use a table saw without a riving knife and guard. When I remove them for dado cuts or tenon cuts, I use secure hold downs. Many woodworkers developed poor habits because there was a time back in the pre 80's days, when saw guards were so poor that it was almost more dangerous to use them. (Remember some of those plastic blade guards that didn't really do anything but show you where the blade was.) Today's saw, since American saws have adopted the riving knife are much better and there is no good reason not to use them.
George Beck
Fishers Laser Carvers