In the real world, I think it'll make precious little difference to the honest man, and probably less to the shall we say less scrupulous, members of society.
For instance, where I live, it has been known for people to park their car in my street off the beaten track for whatever reason they decide, on more than one occasion I have reported vehicles with no tax disc or expired tax disc which had not moved in over a month. I have also reported one which did not show up on AskMid, the local constabulary simply weren't interested and in one case the vehicle sat there for months until the council eventually put stickers on the windows saying that it would be removed etc. Some time later a vehicle came and uplifted it as per the notices.
Personally, I have had a vehicle of my own sat outside for up to two weeks as I had changed from one to another and I was waiting for a buyer for the old one. In my own case, my vehicle was taxed and mot'd, but the insurance had been transferred to my new vehicle. When I didn't find a buyer within the self-imposed two weeks, I moved it onto my nephew's driveway off the public highway and it was sold within a day or so.
In another situation, I unwittingly drove about in an old beat up transit van with my jetski stored in the back for almost 6 months without insurance. This happened because I had been insured with the AA for quite a few years and when the renewal notice came in I simply did as instructed - if I intended to re-insure with them I needed to do nothing as it would be done for me as I pay the full amount by direct debit etc. During this time, I had been stopped twice by police for a routine check as I worked night-shift and it was a common occurrence. It was only when I went to re-tax the vehicle that I discovered I had no insurance as the AA had somehow managed to overlook my renewal and my insurance had lapsed. This problem, of course was entirely my own fault for not checking that everything had been done properly, I'd been with the AA for quite a few years and I trusted them, after all, they are the motorist's friend and the 5th emergency service aren't they? However, no matter how much I ranted and raved at them down the phone not one of them had the decency to say oops, sorry we made a mistake. Needless to say I wouldn't give them even the slightest bit of my time now and I've happily been insured elsewhere since.
Again, stopped by police twice for routine checks in the middle of the night during this uninsured period and it didn't come to light. I know how lucky I'd been and if it hadn't happened to me myself I'd never believe this tale unless told to me by someone I knew to be an honest man. Admittedly, on both occasions when I was stopped, I was in my works uniform with hi-vis etc on and I was always helpful and respectful to the police who stopped me, though on the second occasion, it was quite funny really. The officer who stopped me obviously thought he'd made a good catch, a beat up old transit in the dead of night in the middle of nowhere. When ever I get stopped, I always jump out and meet them halfway and as he approached I got a good look at him, he was a skinny little man with his big traffic hat on and I couldn't help thinking he looked like a nail, just waiting to be hammered into a bit of wood. Anyway, as he walked up to me, is his biggest and most serious voice he said "And where do you think you are going at this time of night?" So, I looked him straight in the eye and, in my best proper voice said "paaardon?" He immediately changed his tune to "I'm sorry to stop you sir but when we saw you go past we thought it would be worthy of a routine check as it's a very late hour to be out and about." I replied, "yep, no problem officer, like you I work unsociable hours and I'm just on my way home from work, how can I help you?"
A quick chat was had about where I work etc., and he let me on my way, but as we parted I told him with a laugh, "I'm glad you didn't want to check inside my vehicle, 'coz you'd probably never believe what you saw in there" so he asked what I had and I told him "my jetski on it's trailer, because I live in a council flat and that is why I bought the transit so I had somewhere to store it." He just shook his head and walked away.
That is the gospel truth, I kid you not.
I don't like the big brother idea of having to insure any vehicle or sorn it - at least I think we should be given a "period of grace" if the vehicle is not being used. I suspect that if you are unlucky enough to come into grief about it with a local plod then I like to think that they would be willing to exercise their use of discretion and allow a little leeway, let's face it, they aren't all power crazy idiots and most of them do use a bit of common sense. If you are genuine, I see no reason why they wouldn't allow you the opportunity to have it sorned, or sorted out. Sadly though, in this age of computerised record keeping, if it says your insurance ran out at 1300hrs then the computer will throw up a flag saying that you're in trouble if you haven't sorned it. I always send V5 documents through recorded delivery if I am posting them, I know several people who have been fined for allegedly not sending in the V5 when they sold a vehicle on, but personally, I prefer to hand it into my local post office as they will forward it free of charge with their internal mail.