Should mass deletion of one's own posts be permitted?

The problem though with (somewhat contrary to the previous item) "No Deletions" threads is the implication that [ETA: mass] deletions are permissable in every other thread: personally, I don't think that they should be (without a valid reason).

As Max put it, insisting that we cannot monitor our own posts is ultimately going down the overly parental response of Skeptiko right before many of us left.

I really dislike mass deletions, but my opinion shouldn't supersede the decision making of others with regard to their own contributions. It's just too hard to pin down what "valid" is going to mean.