This hypothesis is conceptual, and not a ratified scientific theory.
The video segment (shown below) covers Aspect’s 1985 experiment demonstrating how entanglement can be seen — as an entangled state affecting two particles instantaneously:
In this video, Bell states (at that time) he cannot use entanglement as a form of communications. With respect to individual sets of entangled particles/photons as being determined by causality, this is true. However, as a stream of entangled particles independent of causality (being only local) — that’s entirely different.
Entanglement as a non-local characteristic (hence the instantaneous spookiness) automatically disqualifies the phenomenon as a local effect of causality (classical model).
In the aforementioned video, Wheeler goes on to describe the popular concept of “collapsing the wave” i.e. the “irreversible act of amplification” as acted upon an entangled particle through measurement. For such interactions require extracting some form of energy — as required to make a direct measurement of any kind. Enter the uncertainty principle (independent of the observer effect). The probabilistic properties of an entangled particle (superposition) are reduced irrevocably to a single outcome. This outcome as determined by the arrangement of a detector apparatus (at one location), can define the same critical state measured by a second device receiving the entangled counterpart (at the second location).
Modulating the influence of the detector apparatus at the first location (slightly ahead of its counterpart) will allow the detection of changed states in a stream of entangled particles arriving at the second location.
In the diagram below, an apparatus is configured to provide one-way communications instantaneously. As shown, emitter “E” sends out a continuous stream of entangled photons to planet A and B. For the purposes of this example, the manner in which entangled particles are generated, provide a coherent and consistent stream of photons to each location. Further, let it be said that location A is the source of the intended communication, and that location B is approximately one lightyear away from location A.
Let it also be said that emitter E is 10km closer to location A than it is to location B. This shortened distance ensures each photon reaching location A is ahead of the entangled counterpart reaching location B. Using an interferometer or other such device altering a critical property of Photon A — will determine the state of the same property of Photon B.
When Photon B arrives at location B, the critical property will have been set — and measured by an instrument at location B. This can also be done with a polarizing filter (as an example). In this example, a high speed polarizing switch at location A will result in a interference driven signal at location B. Only photons with a sympathetic polarization at location B will register a binary value — all other photons with unsympathetic polarization will be blocked.
This basic concept offers nothing for a feasibility study, however, it’s likely this concept could be tested in the lab.
As for the question of SETI using EM signals (fundamentally unqualified for galactic communications), it’s possible such ‘spooky’ methods might already be used. Were there a known method in detecting the properties of entangled photons from a source light years away, a signal (in theory) could be extracted.