First and foremost, yes, I did accidentally delete one of my character, embarrassing a mistake to admit as it is. I don't consider it Turbines fault that I screwed up, fault lies entirely on me. Luckily however, the character was not my main character and I didn't lose anything important by deleting him. However, I figure if no one makes noise then no one will look into adding safeguards or a character recovery system for the next person who accidentally deletes a character they don't want too.
To be descriptive though in what happened, In my case, I accidentally deleted my character simply because I was tired, not thinking, in a hurry because of dinner being ready, and having character deletion on the brain. I realized I deleted the character I didn't want too pretty well instantly but I may have not even noticed for an hour. Obviously, the writing your character name wasn't enough to prevent me from accidentally deleting the character. I also doubt it would have mattered if you had a third, a forth, or even a fifth confirmation against deleting your character before I would have realized I was deleting the wrong one either (it might help but honestly, I doubt it would).
My suggestion is to add some safeguards against accidentally deletions - either by Game Masters being able to recover said characters and/or (and preferably) with a system that can allow a player to recover from deleting his characters. The idea of Game Masters being able to recover characters has been around long enough that some semblance of what to do should be apparent so I'll just suggest what can be done from the player side of things so that a player can prevent his character from being deleting in the first place:
Add a Deletion Period. Probably one of the most surefire way to prevent players from accidentally deleting their characters is to to make players have to wait long enough that if they have second thoughts or if the character they are deleting is not one they actually want to delete, they can cancel the deletion. Basically, after you have confirmed your character deletion, it sits there until times runs out for it (and then it becomes permanently deleted). This could be a minute, 5 minutes, a 3 hours, a day, a few days - whatever is felt to be an adequate amount of time to be given to the player that if they do have second thoughts they can prevent their character from being deleted or to recognize they are deleting the wrong character.
Of course, even while I don't think it would help, Adding More Confirmations to Deleting Characters would help in giving additional chances for a character to recognize that he's about to delete his character. Though really, if you have deleting enough characters then the process just begins to get tedious; IE, a player will click delete and then may just mindlessly follow the instructions until his character is deleted without a second thought.
Luckily, regardless of whether this suggestion is considered or even read, I will continue playing since I didn't delete my main or some other important character. But without a doubt had that been my main character, not only would I have probably systematically deleted all my other characters and ragequit DDO, I wouldn't be dropping this suggestion here for you to read.
I don't doubt I would have ragequit because that's how I came to play on DDO, ragequitting the last MMORPG because I accidentally deleted my main character. I'll note though that in that MMORPG's case, they didn't have any sort of confirmation when deleting your character; you hit the button and your character was gone, accidentally or on purpose. But really, I don't think confirmations help all that much once your deleted a full legion of characters.