I have posted on a lot of MA forums over the years and when the subject of swords comes up, I tend to be very traditional and conservative in my comments. I tend to find myself giving cautious warnings to dabblers who want a a blade to go out and cut tree branches with, usually just so that they can say that they have a 'real sword'. But sword ownership and use is something that can quicky shift from joy to disabling injury or death.
This fact was driven home for me over the weekend when I was performing a cutting demo. Public demos are fantastic publicity, but I really do not enjoy doing them. As we were setting up, I leaned over just slightly and my thumb slipped off of the tsuba. The sword began to slide out and I went for the grip, but it slid faster than I had thought and I touched the blade. I was lucky. The cut was deep, but no tendons were cut. One of the guys wrapped me up nice and I was able to perform the demo that is pictured on my page. Then I went and got five stitches and performed the afternoon demo, sparring, cutting and all.
This wasn't to impress my class mates; I was so pleased to still have full use of my right index finger that I was happy to continue.
The environment was noisy and concentration was not easy to maintain. In that environment, even being careful, mistakes are so easy to make, even by a trained professional like me!

Daniel