Peter said:
(1) "you seemed to work off a false assumption (common it seems) that they somehow 'check on' the spin state prior to 'measurement'. Which they don't."
I don't work off that assumption.
(2) "What is actually being 'measured' and compared is a 'difference', not any actual spin state."
What the experimenter is intending to measure is irrelevant.
(3) "You seemed to deny any effect! Can you please review that assumption too as it seems clearly wrong (though again perhaps no uncommon!). If you disagree, please justify your assumption."
I don't deny any effect.
============================================
I'm interested in loophole free Bell-CHSH type experiments.
These are defined in terms of an experimental protocol. Not in terms of any particular physics.
Here it is:
Alice and Bob are in different classrooms and in each classroom there is a magic black box, called "measuring device A" and "measuring device B" respectively. These two boxes are connected to another magic black box in another classroom, called "source", through some kind of cables, tunnels, or whatever. Anyway: all three black boxes had means to share any information they like. What's inside those boxes and who made them for what purpose is irrelevant. Alice and Bob's boxes each have two buttons, and two lights. The buttons can be pressed, the lights may or may not flash.
Now observe carefully:
Step 1. The connections are severed.
Step 2. Alice presses a button marked "0" or a button marked "90"; Bob presses a button marked "45" or a button marked "135". After Alice and Bob have each pressed a button, a red or a green light flashes on their box. They record their input and their output.
Step 3. The connections between the three magic black boxes are restored.
Steps 1 to 3 are repeated, say, 10 000 times. In between each repetition the two magic black boxes are briefly connected to another magic black box called "source" and then disconnected again.
It then turns out that
Prob(lights flash same colour | 0, 45)
= Prob(lights flash same colour | 90, 45)
= Prob(lights flash same colour | 90, 135)
= 0.15
Prob(lights flash same colour | 0, 135)
= 0.85
Please implement this using your spinning disks or cards or whatever. You can put anything you like in the blackbox and use whatever communication channels you like between the three.
If you think you can do it, please write a suite of computer programs which simulate your experiment, and win the Nobel prize.