A huge Australian store put up seven-storey-high banners across Australia that included a misplaced apostrophe. Grammarians may bemoan the level of literacy of the average Australian, but from Myer’s point of view, far too many people saw the gaffe and Twitter exploded with tweets about it.
For writers, and anyone anticipating a career in retail, here is how it works:
Possessives: My dad’s hat. Thomas’ hat. (some older and more traditional publishers still accept Thomas’s hat). The Joneses’ hat.
Plurals: No apostrophe. Cats, hats, the Joneses. (And in this case "gets".)
Plural and possessive: the cats’ hats, the scissors’ blades.