I'm not sure it is loophole free. There is a potential major problem using photons. If I think a photon will go through gate "A" it will go through gate "A". If I think it will go through gate "B" it will go through gate "B". I wouldn't make the following criticism, but I suspect someone else might. Depending upon the outcome the criticism would be "the photons became entangled because the experimenter thought they were;: or "the photons didn't become entangled because the experimenter wasn't thinking clearly."

It might be possible to prove entanglement by using something relatively large like a pea for example. Unfortunately the failure to show entanglement between two peas would only indicate that entanglement of larger objects was not possible, but entanglement of individual particles might be.

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