A new paper to be published in Nature appears to have closed the "freedom-of-choice" loophole in the standard Bell-type experiment.
The BIG Bell Test asked human volunteers, known as Bellsters, to choose the measurements, in order to close the so-called "freedom-of-choice loophole" -- the possibility that the particles themselves influence the choice of measurement. Such influence, if it existed, would invalidate the test; it would be like allowing students to write their own exam questions. This loophole cannot be closed by choosing with dice or random number generators, because there is always the possibility that these physical systems are coordinated with the entangled particles. Human choices introduce the element of free will, by which people can choose independently of whatever the particles might be doing.
Participants contributed with more than 90 million bits, making possible a strong test of local realism, as well as other experiments on realism in quantum mechanics. The obtained results strongly disagree Einstein's worldview, close the freedom-of-choice loophole for the first time, and demonstrate several new methods in the study of entanglement and local realism.
I have not read the actual paper yet, so if you have, I'd like to hear about it.
From my personal point of view, I no longer consider that the loopholes of Bell tests are anything significant anymore. This is due to the NUMEROUS consistent and non-contradictory results that we have obtained so far. In terms of the physics, Mother Nature seems to already let us know what she really is in this regards.
But I guess, until all of the loopholes are closed, we will always have to find a way to close them.