less versus fewer

Abbreviations are used all the time, and if you don’t recognize that and try to parse an abbreviated expression as it it were a complete expression, you wind up with recommendations that sound false to native speakers, but who are afraid to say so because they can’t put their finger on the theoretical error being made. So, in the supermarket, we see nonsense like ’15 items or fewer’ used to designate the express checkout area. The sign should say, as it did in the good old days before mush-headed hyper-correctness took over in the wake of rampant political correctness, ’15 items or less’. This is correct, because it is an abbreviation for ’15 items, or a quantity that is less than that’.
keywords: life, language, grammar