Ok so most try to read the environment and just by the feel. I do too well try too. Lots of shooting I do is around corrals and in bare fields....nothing to really go off which is the hard part. More a shoot and see where it went then correct. I today was shooting which I couldn't barely feel the wind but then tied a ribbon on the front and was quite a bit telling. Also showed just how shifting the wind could be here.
Alot of my prairie dog shooting is just that, either walking in the shots, or the first miss gives a nice puff of dust/dirt to indicate which direction and how much the wind is blowing out at the target. (Works best before the dogs get smart to what those dirt puffs represent)
What you're talking about is the challenge of Xtreme Field Target. The maddening, frustrating, addicting challenge of XFT.
The windicators tied on guns give the shooter an idea of what it's doing at the shooting position, but the wind is often doing something completely different out at 75+ yards. My best scores in XFT have come when the conditions allowed me to see the mirage out at the target. When you can see mirage, you can tell if the air out at the target is pretty still b/c the mirage will bubble straight up. If the mirage is trickling to the left or the right it gives an indication of necessary hold off left or right. And finally, the degree to which the mirage is boiling helps to know how much hold off. In a stiff wind out at the target the mirage will be moving almost horizontally. Think wind driven rain moving more horizontal as it falls in a stiffer wind. Falling rain is just reversed as it's heading towards the ground while the mirage is traveling upwards. And sometimes you get a chance to see the mirage going in two different directions, at mid distance and far distance, which is really tricky to then decide what to do about it when you take the shot.
There's a lot of skill to it and I don't profess to even sort of have it mastered. Seeing the mirage is the first part, the hard part is being familiar enough with your gun and pellet and how they behave at the speed they're being shot to know how much to hold for what you're seeing in the mirage.
As for the benchrest guys who put a bunch of flags up ....I acknowledge the skill in what they're doing, but I can't get on board with the idea of a plethora of wind flags. Reading wind flags is indeed a skill, but one of limited utility. The only time a shooter is going to be able to utilize that skill is when they shooting benchrest, over the top of a bunch of wind flags. I much prefer the concept of learning to work with what you have, be it leaves or grass or branches or mirage or hair on your neck and arms or a combination of all that, over wind flags.
And for sure, put a benchrest/wind flag reader up against a "hunter" and have them shoot over a field of wind flags and the wind flag readers gonna win, BUT take away the wind flags, in perhaps a hunting situation or an XFT situation, and the wind flag readers going to be struggling in the absence of flags.