Sorry I'm out. I like to see myself as a trusting individual but doing the experiment as you describe, as Zep and I are discussing, opens the door for collusion. Imagine if you got great results. Would you accept them? Would a wider readership accept them? Or would collusion be brought in as an explanation? If the latter then I would see the experiment as a waste of timeI think the latter is inevitable.
The main problem I have with Sheldrake's latest set of internet experiments is that he does precisely this. He is basically inviting participants to conduct an experiment whereby two people each look at a separate computer screen that could display two possible pictures, the same pair of pictures for each person. One person has to guess which picture the other is looking at. So Sheldrake is looking to see if the hit rate is higher when the pictures are the same, a kind of reinforcement model of telepathy. A good experimental idea, except its done over the internet! Which means both lookers could be in the same room for all we know!
I doubt Sheldrake is planning to draw grand conclusions from an uncontrolled experiment like this.
However I expect the purpose is his aim - which I think is laudable - that the general public should be able to test things for themselves (cf the staring experiments). Which is a way of popularizing science, and also I think a way of side-stepping what Sheldrake sees as entrenched opposition from the scientistic establishment. I.e. he's saying to the public, 'if you think there might be something to telepathy/staring/whatever, why not test it for yourself'.
People who are genuinely wanting to test for their own interest will not collude (though I don't deny unconscious leaks would also need to be minimized, and perhaps some could not be eliminated in an informal experiment; though even from what I recall of the staring experiments you can easily remove pretty much all leaks).