Yep, I do it, and I will also “straighten” out a curve in the road by crossing the double yellow. We have a lot of curvy roads in WV. I have seen the DPS do it this way.
In Spain it would be illegal, same as 3-point turns (this being the reason why I flunked the practical when I got my Florida driver’s license, I couldn’t grok the concept). So since I learned to drive in Spain it’s not something I’m likely to do.
Start the blinker well in time, yes. Hug the center of the road, yes. Drive in the opposite-direction-lane hell no.
Many, many times I’ve seen it and done it out in the country where I lived during my first marriage. When you’re only one of a handful of cars using that road it’s commonplace.
I most often saw this manuver done at folk’s driveways, which would be at 90 degrees to the ‘main’ road. You have to practically stop to make such a turn. If you use this manuver, you can go as slowly as you like, or even stop briefly and check the mailbox without impeding your neighbor behind you.
Do you have those places where you can ‘straighten out’ an S-curve only in the winter time of the year? We had a couple of those too.
I see this done sometimes by folks who must hate seeing speeding trucks or cars bearing down on them while they slow down to turn. Most often done by farm tractors in areas of wide open visibility. They are in a hurry to get off the highway usually - I never do it at my turnoff as it is a double yellow and there is a short hill and at anytime an 18 wheeler hauling logs may come barreling over the crest.
Passing on the shoulders is ticketable offense here, but not if there is a specific passing lane created in front of a intersection to prevent those slow downs or opposite lane left hand turns. The county finally installed one of those passing lanes in front of my road, after a collision occurred with a motorist passing on the left and someone pulling out of my neighborhood.
I do it, at least a couple of times a week. It’s a courtesy to the driver behind you, so he doesn’t have to slow down and/or stop while you make your turn. Not a big deal out here in the sticks.
Done it. Seen it done. So what?
The way we were advised to handle such situations in New Zealand would be to pull over as close to the shoulder as possible and let the trailing car to pass before making our own turn.
And as has been said upthread, if I saw somebody doing that I would not pass them as I could not be sure what they were going to do.
I’ve done it and see it often in rural areas in both B.C. and Alberta.
Long stretch of road…visibility is good…no traffic coming…I do it nearly every time if a car is behind me and have seen it done often also.
I’ll do it. Climbing the pass to the continental divide, my turn is a left. It’s a ‘Y’ turn onto a gravel road that I can do at about 35 mph. If traffic is clear, I will signal my intentions and get out of the way before my turn so as not slow the people behind me that are trying to climb up to the pass.
It all depends on the situation and traffic.
What I really hate is when people wave you on when they clearly have the right of way, but are too clueless to realize it. They just need to do what is expected of them.
I do it all the time, making the left turn to the back road coming into town. I can see clearly that there’s no one on the road ahead and no one on the road I’m turning to (and no yellow lines).
It’s as much for my own safety as a courtesy thing. It’s a back road, and I’m never sure that the guy behind me knows where I’m going to turn, because the next turn is the main road. Even though I signal in plenty of time for the guy behind me to back off, sometimes they don’t.
Ah yes, the ever-popular “I’m a better driver than everyone else” excuse. As in the example I gave, people think they see things (such as a clear lane) that they didn’t really see all the time. Ever read about one of those experiments where an incident such as a purse snatching is staged and afterward every witness gives a different description? Hell, why not just drive down the left side all the time, as long as (you think) nobody’s coming?
It’s an unexpected maneuver. Drivers who do this are in a place that they are not expected to be. And it’s not unreasonable to expect the following car to slow down for someone making a turn. Oh the horror, they lose a few mph for a few seconds. So after the other car makes the turn, they accelerate again, and life goes on.
This “courtesy” is just as “courteous” as the mooks who have the right-of-way but “politely” let other people go instead, as at a four-way stop, or stopping in traffic to let someone pull out. It’s unexpected and dangerous.
Yes there are a lot of those when the snow is on!
Another “seen it and done it” here in Illinois. Mostly on flat, rural two-lane highways where the speed limit is 55 or 60 and you don’t want to make the other guy slow down to 10 or 15 while you creep into the tiny side road or driveway.
For those saying you couldn’t be sure what they were going to do, why not? If they put their blinker on in advance, you already know they’re turning left, and when they get in the other lane, you should both be able to see there is no one coming or else I’ll agree it isn’t safe. But it is an efficient use of the roadway and, for the most part, legal and safe.
How much time can that possibly save the other driver? Four seconds? Five? I’m betting less.
It hardly seems worth it, given the risks.
How are we expected to see what’s in front of us in our own lane but it’s a figment of our imagination if we look into the other lane? 
How do we drive in the first place without being omnisciently aware of the fact that there aren’t stalled cars in our lane directly in front of us? How can we be sure a drunk isn’t bearing down into oncoming traffic right into us? How is getting into the left lane to pass someone legal and safe but when you get over to slow down and turn suddenly you can’t trust your senses?
It isn’t unexpected to me and quite a few other drivers in this thread. It is a safe, courteous, everyday occurrence.
Now this is something we can agree on! 
This is legitimately unexpected behavior and throws the entire concept of right-of-way out the window. I wouldn’t say it was dangerous necessarily, but it slows things down and confuses everybody rather than helps.
I’m going to guess that you spend very little time on rural roads. What the OP suggests is not in any way putting any one at risk. In fact IMHO, it makes things safer.
Guess again. If your definition of “rural” includes farmland and horse country.
How so?
I agree completely.