WOW JEES!! O god these things are sounding more and more dangerous! I was planning on wearing normal sunglasses but now I'm goingto hunt down some real eye protection. Thankyou so much for the warnings!
To be perfectly honest I was using a different tool when I got my scar. 99% of the time nothing will happen, I was lucky that my 1% ended up being no big deal, but proper safety equipment is always a good idea. Especially when dealing with power tools that spin fast enough to cut through fiberglass.
Don't be afraid of your tools, just use common sense and think about what you are doing. All will be well