Since when is 'z' used to indicate plural?

In 1968, there was a top 10 hit in the US titled “Noboby But Me” by The Human Beinz.

If you ever walked into a “Sheetz” store, you would spotaneously explode at the selection of BurgerZ, Hot DogZ, NachoZ, and CoffeeZ that they sell.

Well, [z] is one of the three allomorphs for the /s/ plural suffix in Standard American English, so if we Linguists could only get the folks who make Scrabble[sup]tm[/sup] to include the open & close square brackets, the issue would be a nonissue.

Come to think of it, is there such a thing as a Scrabble[sup]tm[/sup] set for the International Phonetic Alphabet (not, mind you, the alpha-bravo one of NATO fame–the one used by linguists)?

But Monty when will we get 1337 Scrabble[sup]tm[/sup].
That will be a sign of the apocolypse.

4|*0(01’/|*53