Part of the challenge with guards is the design of many of the guards. The ideal setup is a riving knife and an over-arm guard so that both through cuts and non-through cuts can be completed without removing the gear. That's not the case with a huge percentage of table saw that are actively being used every day. It's true in my shop, too...the blade guard that came with my particular sliding table saw attaches to the riving knife and therefore, it must be removed for non-through cuts. It's also not clear so it does interfere with sight-lines, although I agree that if a cut is setup properly, it's not necessary to actually "see" the blade making the cut to make the cut, if you catch my drift. When I had a true over-arm guard on my previous saw, it stayed in place 99% of the time. (Of course, that saw didn't have a riving knife...but that was the generation of machinery it came from) I do plan on rectifying this at some point and fortunately, I use my slider such that most of my cuts do not have my hands near the blade and those that do have the fence in the low setting and an appropriate push block/stick in use. I almost never feed material with just my hand. But you know what...despite the care I take, I could still have an incident just like anyone else can experience the same. "Stuff" happens...