But, I dare him to show in usable form the general solution for even servings to be distributed to N partygoers.

I'd rather have the dried out edge than his hands smashed into the icing as jams the pieces together. Picture that with regular frosting!

but also the rubber band.

Eat the whole cake! Nothing left to dry out.

You use this stuff that's been around longer than that idea, and it's called "wax paper" (also available is baker's parchment paper and plastic wrap.) Just press a piece of that into the surfaces that are exposed, and nothing will dry out.

+ I never refrigerate my cakes. I use this contraption called a cake stand with a cover. I have never had a problem with dried cake slices, unless I leave it out, instead of leaving it in the cake stand.

Science needs to take a break from trying to "prove" a theory when dealing with things that already have verified solutions.

I'm lucky if it lasts by day two just sitting in a cake cover on the counter.

I have 4 kids, 2 are teens, 1 is a preteen. My oldest knows how to bake. Sometimes when I'm not there because I'm in class in the evening, she'll bake a cake for her and her sisters, and when I come home, they've saved me a piece. "A" piece. LOL. Same with brownies. It's like scavenging starving hyenas around here when someone makes brownies.

brownies or a cobbler...You almost need a commercial sheet pan!

You are going to have more of a job moving the halves together. Possible but you'd need tools.

You could slice it like a loaf of bread from one side--that way you'd have one cut surface to cover with plastic wrap--easy-peasy.

the triangle slice is much prettier in my opinion and says YUM to the eyes. A flat piece of cake with the icing hiding down the side says sad to me.

Of course anyone making a plain boring cake like the one in the video won't care.

cake, I automatically halve it, then cut in 4ths, then 8ths, etc., always making sure that I have at least one slice per person plus an extra one for the cook.

Dental floss. Used to do this at birthday parties

the *&()_^@ layers come out even. I bake rectangular cakes. And they're moist enough that they don't dry out in one day.