[mcintyre1994]

I still think a confirmation with "Don't ask again" is a much better solutions.

Power users see it once, understand what'll happen and turn it off, no annoying confirmation after they've identified as a power user.

Novice users would, I think, feel better about a confirmation than an undo - if you need an undo you've made a mistake and that's not a good feeling, if you see a confirmation the service is looking out for you.

[gmac]

I think both theory and data are against you here.

e.g. http://msdn.microsoft.com/en-us/magazine/cc163835.aspx

[mcintyre1994]

Fair enough, you could be right - that's a well written counter-argument. However, while data might exist that users hate confirmation boxes, even those they can ask never to see again, and prefer undo, the cited articles doesn't contain any. It's not a Microsoft employee either, so the author doesn't have the sort of Windows data we often see in Microsoft blogs on UI. I'd also point out that the confirmation box example in his picture, for example, doesn't include an option not to show it again. It's also an undoable action as he points out, and I'm certainly not arguing that we should include both.

All that said, I can certainly see reasons for both - it's probably not really a black and white issue.