Debunking Glider Spoiler Turns Causing Spin Thinking

I am convinced that the airbrake is the least understood of the glider controls.
In order to give an opinion on the subject of airbrake use in turns, perhaps we should go back to their use as a glidepath control device.
I've heard many pilots explaining how the airbrakes work saying something like "When you open the airbrakes, the lift on that part of the wing is reduced or eliminated. Since you have less lift now, your vertical speed will increase and you will sink faster". Wow. And wrong, except for an instant after you open the airbrakes.
When you open the airbrakes, the lift on that part of the wing is gone, true. But only for a few moments, after that, the angle of attack, the airspeed, or both have to increase to create enough lift in the rest of the wing in order to hold the weight of the glider. Otherwise the glider would keep accelerating in the vertical direction.
If you try to keep the same airspeed when you open the airbrakes, the angle of attack has to increase. That means that you are closer to the stall, or conversely, that the stall speed increases.
Right when you open the airbrakes the total lift is reduced. This gives a nose down pitch tendency, but the extra drag causes some nose-up pitch tendency. The net effect is that some gliders tend to accelerate and some tend to deccelerate when opening the airbrakes. After a couple of seconds the glider is stable again in a steeper glidepath.
It is never a good idea to make big changes in the airbrake position on the flare because you risk a heavy landing or a ballooning.
Now, to their use in turns...