Ok, seems pretty universal that it’s just a local wifeism.
To be fair, it was a little good-natured busting of chops on her part as well. Plus she’s usually right about everything, or should I say, “confidently correct”.
Never heard the term before. I would have guessed it meant parking across the lines or otherwise haphazardly.
Back-in parking is something I never do. I get that it makes it easier to leave the parking spot, but you’re just trading the very small inconvenience of backing out for the much larger inconvenience of backing in. It’s not worth it, IMO.
At least when backing into a space in the parking lot you’re much less likely to hit someone who’s also moving and not paying attention to you.
I park front-in at the grocery store so my tailgate is accessible, and I don’t know how many times I’ve had near-misses when backing out because someone else is backing out and not paying attention to me, or someone is speeding down the aisle way too fast and also not paying attention.
From SW Michigan here. Never heard of granny parking. The people I usually see backing in are pick-up truck drivers.
Yeah, if you have a long vehicle like a truck, it’s easier to turn into a parking space straight if you do it in reverse.
IME, a substantial number of drivers in my area who back in to park are lacking even those very minimal skills. 
Yes, my state has all of these elements in the road test. You’re also supposed to know how to park on a hill.
One website (not an official one) advises backing into a parking space at the state police facility when arriving for your road test, to avoid stress when the test starts. You’d think it would add stress if the only parking spaces were surrounded by other vehicles and tense applicants feared grazing other cars while backing in.
*On the list of “automatic road test fails” is a situation where the examiner takes control of your vehicle as a result of hazardous operation. How picky.
I call bullshit (in a good-natured way) on your wife. Someone in her family probably invented the term. A term which, as previously discussed, makes zero sense.
mmm
Oh! I’ve never heard this term and virtually everyone I know of all ages pulls through whenever possible because why wouldn’t you so you can easily see while leaving? However, in this state it’ll illegal not to have both front and rear plates displayed so the scanning problem obviously not an issue here.
As for the OP’s question, I’ve never heard the term either. My guess was that’d it be the little old ladies who s-l-o-w-l-y inch their cars forward until they just barely touch the bumper of the car facing them, then back up a couple of feet. There’s no term for that here either, but it’s something I’ve seen several times, so…
The rationale I’ve heard most often is that there may very well be another vehicle about to pull into your planned parking space from the other side unseen by you (given the prevalence of SUVs and the like these days), and that could result in a fender-bender and/or some interpersonal conflict between the other driver and “the asshole who stole my spot,” i.e., you.
These are the arguments I’ve seen against backing into a parking space:
(1) Depending on the configuration of the parking lot, as you back in there will be one of three things behind you: (a) another car in the next aisle; (b) a walkway, or (c) a wall. It is alleged that drivers backing in, being typically insufficiently skilled at doing so, will bump into the wall or car behind.
(2) In the case that there is a walkway behind: Note that cars stick out farther in back behind the rear wheels than they do in front beyond the front wheels. If there is a walkway, then there is probably also a curb at the back of the parking space. Drivers will back up until they touch that curb, and the back end of the car will project into the walkway, obstructing it (more so than if the car heads in).
In my case, I always back in until I touch the curb, and then pull forward a few inches.
ETA: Example of typical car: Note it stick out farther in the back than in the front:
Yet most people manage to parallel park (backing in) without hitting the car behind them all the time.
Yes, and how in the world is it possible? I tells ya, it’s a mystery right up there with how bumblebees can fly!
This was similar to my guess except that I would have expanded it to include any parking with innumerable adjustments to get in exactly the right position.
Backing into a parking place has always been referred to as ‘combat parking’ for everyone it’s ever been a topic of conversation with around me. And it’s been my preferred mode for 35 years now.
ETA Googling ‘granny parking’ resulted in no matching hits while ‘combat parking’ yielded pages.
Lifelong Wayne and Oakland resident as well. Never heard it either.
Never heard of it. I would have guessed it was slow and/or imprecise, somehow annoying to other motorists.
Why the assumption that grannies are bad drivers? Same with granny knots to describe an inferior knot. My granny could parallel park and macrame a tea cozy at the same time.
Just wanted to make it unanimous and say I’ve never heard of it. I guessed wrong and would never have guessed it correctly because it makes no sense.
This granny thanks you 
Never heard the term either. I’d have guessed it to be a zillions-of-iterations version, or badly across the lines, or some such.
Backing in is more of a jerkish thing to do in a busy lot, as it typically takes longer than backing out does. Maybe it’s faster / easier with a car equipped with assorted cameras. Pulling through, on the other hand, I’ll do when I get the chance - though invariably this will result in my coming out with a cartload of groceries, and having a lot of trouble loading them into the back as a result :).