Photons Detector not yielding "which-path" info. In Fabric Of The Cosmos, I am just getting through the part where Greene discusses a multi-path setup (7.5?) involving a series of beam splitters and downconverters, whereby photons striking two of four detectors will yield definitive "which-path" information, but, due to the configurations of the optical components, "hits" on the other two detectors will not yield definitive which-path info, and therefore, we preserve the interference pattern that one would expect without any measurement intervention. It seem that the system "knows" that our experimental setup can not, or does not, provide which-path info and therefore behaves accordingly. So, what if the detectors were present, but not "ON" or functioning in any way. What would we expect then? What if they were on, but the wiring was sabotaged such that the result would never be reported reliably? What if the result were available, but only sent to a computer that was programmed to irretrievably delete the data and never make it available to living beings? Or what if a long delay line were in the system such that the result were not known for some time after the photon struck the detector. Would the interference pattern break down at the instant the photon struck the detector, or only after the result was "known.?" Thoughts?