SAS, show of force sometimes works, sometimes doesn't.
Depends.
I was in the Mideast in 2004, and Show of Force was a typical mission requirement, thanks to the RoE. A lot of times, the powers that be wanted weapons release, like a GBU 12 or GBU 31 or whatever was loaded, to be a last resort. I think that frustrated the ground guys more than a little bit, but at other times, it was the ground commander who was very strict on there not being bombs dropped since he had some political realities on the ground with locals that would be screwed if bombs started dropping in that local area ... yet again.
Nothing is simple in COIN, nor in post-conflict operations stuff.
It's all a bit of a mess.
Now and again, when our ground guys were engaged with folks in houses (in Iraq) and the go fasters (F-16 and F-15 mostly, and Tornados) made that low speed pass, without weapons release, they'd get some of the folks shooting at them to surrender, stop fighting.
And more often, it either got their heads down or had no effect.
As I said, it depends.
There was a story going around about some high speed passes in Afghanistan by B-1's at supersonic speeds that apparently scared some Taliban, or Muj of some sort, into moving, which got them hit by small arms fire from local Coalition forces.
That's another possible outcome of a "show of force" by air assets.
Show of force frustrated quite a few fighter jocks, since making that low speed "scare them" pass also put the jet into MANPAD envelope.
One never really knew how many MANPADS were in anybody's hands ...
My further comments in re the RoE and some of the political crap the operating forces have to mitigate are censored to keep my blood pressure down.
ADDED LATER IN EDIT:
For John D et all VRS flying things ...
The 40/800 guideline, which we used as a rule of thumb when teaching steep approaches in the SH-60B, back when I was an instructor, was used to prompt when to wave off a steep approach so that YOU DON"T PROCEED TO GET NEAR OR INTO VRS.
That close to the ground, below 500 feet, usually somewhere near 300 feet AGL, if you actually enter into VRS and got the RoD and handling changes/problems John describes, your chances of waving off successfully aren't good.
I note that when checking this out, John took the bird up to 6-8000 feet.
There's a very good reason for that.