When you practice gun disarming techniques, do you use a real, loaded gun? Most people would be shocked at the idea. Many of these same people, however, will take out a razor-sharp sword or kama (sickle) to practice a weapons kata.
It should go without saying, but must be said anyway, that a person who practices with a live blade is an idiot and will surely bleed. Ask any sensei who has been around for a while. He's seen it.
Just recently Shihan Tom Frobel regaled me with a tale of a sword demo gone wrong in which the demonstrator managed to slice through his own Achilles tendon while showing off with a live sword.
"Live" has two meanings. One is "sharp." The other is metaphorical. The best policy with weapons (of all kinds) is to treat them as if they were possessed by demons. The weapon is alive. It has a spirit. The spirit is malevolent. The sword wants to hurt someone, and if you give it a chance, it will succeed. It is the same with all weapons, including firearms. Perhaps especially with firearms.
The applications of the shotokan katas involve weapons. Use bokken. Don't be an idiot.