[FlyFish]

I don't see any problem, either, and seem to recall doing the same thing a few times over the 50 years I've been reloading. Certainly would appear to be safer than punching out the live primer (which I and others have done many times without incident), then resizing. As you know, the shellholder has to be open in the center to allow depriming, so no pressure would be placed on the primer during your resiziing operation.