I wonder if Sir Francis ever had to cut cake for a bunch of kids. Mine would always complain that their sibling's piece was bigger than their own. His technique provides a continuously diminishing length of the cake slice- guaranteed to promote sibling friction.
My wife, now retired, ran the kitchen at our synagogue for many years and catered hundreds of bar/bat mitzvah kiddush luncheons and dinners along with a few weddings. I can assure you that the Health Inspectors would frown upon your practice in that environment! What you do in the privacy of your own home is of course beyond the reach of those noisome bureaucrats..... personally, as empty nesters, we use individual challah rolls Friday night, warmed in a convection toaster oven.
I have forwarded a link of this article to my grandsons' parents. We just returned from visiting our youngest one for his first birthday. He didn't care how the cake was sliced as long as he got PLENTY! He is already an omnivorous chowhound (a family trait except for the oldest grandson), albeit with only 6 teeth....quite adequate for cake!