I have noticed this is definitely a "thing" presently, couldn't begin to count the number of cars I see on a regular basis in Glasgow and Edinburgh that are not sporting a front plate.
It is most definitely a legal as well as MOT requirement though, so surely it is likely to cause the owner all sorts of grief if stopped by the Police or involved in an accident.
Insurance companies could potentially claim that the vehicle was not road legal etc etc or start to look a lot harder at the car in question for any other undeclared modifications.
I had the misfortune, last year, to meet a certain P.C. Shiny Buttons in his stealth, unmarked BMW.
I was driving our Volvo T5 which has a short (5 character) plate that is legal to the mm.
I saw him double take my car as he waited to join the roundabout I was on, and sure enough a mile or so along the road he "de-cloaked and gave the benefit of lights and sirens.
Now as I had already spotted him I was being very well behaved, as in fact I had been when he first saw me, so I was more than a touch surprised to get the full treatment.
Anyway we met on the hard shoulder and he went through the usual "do you know why I stopped you"dance. Unusually, his passenger had accompanied him, rather than sitting in the car watching.
When I replied that I had no idea he guided me to the front of the car and pointed out my number plate. His take was that the plate was too small to be legal and the spacing between the digits was also too small.
I always have my plates made by a local number pate specialist, who have supplied the trade for decades, and they make the plates exactly to legal specification, so I felt very certain that the plates were perfect, doesn't stop you feeling a bit nervous at the roadside though :?
To my utter surprise, he produced a small flexible ruler, like you might get in a Filofax, and began measuring every gap. Side edge, top edge, bottom edge, character to character in minute detail.
As he was doing so his colleague caught my eye and he rolled her eyes and shrugged in what I took to be an apology for her partner.
Finally, after an Olympic bout of measuring he moved to the rear of the car and gave the rear plate the full and lengthy benefit of his Mark 1 Eyeball before finally declaring himself content and sending me on my merry way.
Needless to say I am at a loss every time I see a plateless vehicle but it certainly seems, to me, to be just begging for trouble.