In segment 23 of From Camera To Print, Michael taped the mat board to the backing board. In Issue #15 of the LLVJ, Bill Atkinson did not. What's the thinking on this?

I've never seen this technique used for archival matting. Usually the mat overlay is hinged at the top so that it can be lifted. I would think that taping the overlay to the back board would not be a desirable thing to do as you would probably have to destroy the mat if it was ever necessary to reach the print for any reason.