OK, here is an interesting assertion I haven't seen before. Thought I would see what some of the folks here think. The paper is: Quantum Preferred Frame: Does It Really Exist? by J. Rembielinski, K. A. Smolinski (2009) Abstract: "The idea of the preferred frame as a remedy for difficulties of the relativistic quantum mechanics in description of the non-local quantum phenomena was undertaken by such physicists as J. S. Bell and D. Bohm. The possibility of the existence of preferred frame was also seriously treated by P. A. M. Dirac. In this paper, we propose an Einstein-Podolsky-Rosen-type experiment for testing the possible existence of a quantum preferred frame. Our analysis suggests that to verify whether a preferred frame of reference in the quantum world exists it is enough to perform an EPR type experiment with pair of observers staying in the same inertial frame and with use of the massive EPR pair of spin one-half or spin one particles." In essence, they argue that there is a specific - and TESTABLE - difference in the quantum predictions (spin correlation of entangled pairs of electrons or protons moving in opposite directions at a very high velocity) between these 2 important scenarios: a) There IS a universal preferred reference frame (key to many non-local Bohmian type theories), and the standard CHSH inequalities hold (QM prediction of about 2.8 violates local realistic upper limit of 2.0 at all). If this were true, it would be powerful ammunition for Bohmian class theories and non-locality. b) There IS NO preferred frame - as expected per virtually all formulations of relativity, BUT the standard CHSH predictions of QM require a relativistic correction which drops the predicted value below the local realistic upper limit of 2.0 when the associated velocity v exceeds about 80% of c. If this were true - you would expect it would be - it would lead to some very interesting ways to probe entanglement in the relativistic limit; and would rule out non-locality as described by most Bohmian theories. The authors describe prior experiments in which entangled proton pairs have been observed at v of about .40 to .50 c, but these velocities are too low to see any measurable difference between a) and b) above. By increasing v, such experiments could distinguish between these scenarios and settle a very important point in quantum theory... assuming the authors' theoretical analysis is correct.