Ok, I didn't really want to get into this, but as the person who has been in knife manufacturing for almost 30 years and the person credited for startIng Shun and the owner of Apogee, I have heard more opinions and theories on the dishwasher than I can count. Inspector Poirot is correct, depending on the steel, extended periods in the dishwasher could affect the tempering. However heat treating usually involves temperatures that would melt plastic. So if your plastic spoon is holding shape and not turning into a pile of goo, you are probably fine. When we first started Shun, we ran it through the dishwasher 500 times. There were some minute changes on the edge, but nothing to write home about. We did the same with Dragon, and really saw no change. This was because both of these steels were hea treated to an above 60HRC. knives in the mid to lower 50'swould show more damage.
So now I'm going to offend some people, but here is the truth. There are very few things we agree on as an industry. The dish washer is one. Doing this is an express train ticket to stupid town. I am not speaking from theory or opinion, but from fact. It is one of the number one causes for trips to the emergency room from the kitchen. You can give me all of the excuses and justificactions you want, it doesn't change the fact. It's dangerous you shouldn't do it.
So why don't knife companies warranty for the dishwasher? I just told you it really doesn't affect the blade that much. It's the handle that fails. Materials like wood, pakkawood, and POM, get trashed in the dishwasher. First they are subject to almost boiling water which causes swelling, then heat drying which causes shrinking. Over time this will cause warping, rot, and cracking. Knife companies can fix blades, but they can't fix handles. This is why they tell you not to put in there.
The only materials that will hold up, are micarta and G10. Dragon uses Micarta, because I'm smart enough to know that all of my soap box screaming won't really change your mind. The sad fact is that it's going in. So the Dragon knives warranty does cover the dishwasher. But for the love of god, don't do it. If someone you love reaches in and seriously hurts or even maimes themselves, you will never forgive yourself. Do you have any idea how many nerves and tendons are in your hand that can be severed? The worst I ever heard was a child who was a prodigy for the piano ended her future destiny when she severed a group of nerves in the palm of her hand. So please, just don't do it. PLEASE!!!!!!