> It’s as if people think that the mere act of picking imbues their ticket with a bit of juju, which makes them less willing to part with it.

No, the mere act of picking imbues their ticket with a bit of guarantee that you haven't maliciously selected numbers that don't win to cheat them. And I'd expect people's psychologies to pick up on that even if they can't explain why.

Even if that actually was the study that was conducted, it still wouldn't support belief in juju as an explaination.

And not considering that people might react strategically to the mechanisms of your experimental/intervention setup does seem to be a reccuring problem in social science/policy.