There is a reason why those experiments don't work.
What is to be remembered is that when we talk of spiritual life.....'up' and 'down' don't mean anything....much like in outer space. Its gravity on earth that creates this up and down.
Its like Parallel Universes existing inches away from us. Are they up or down or where?! They are just there around us everywhere.... in some sort of another dimension or something.
Similarly, when people leave their bodies and go 'up'... its not really meaningful in a physical sense to talk of a 'up'. Its not that they go to the floors above and see all other patients on those floors....and not the ones on the floors below.
They just go into another dimension that we can only refer to as 'above'.....but they need not see all things situated physically above the patient or the room.
Its also a moment when the patients are in a strong mental and emotional state....such that what they desire or feel is seen more intensely than things they don't care for. They are drawn towards things they feel strongly about.
Its not a casual fly by....looking around at all sign boards on the way.
So, you immediately limit yourself to your idea that the 'spirit' body moves into another 'dimension' where they don't necessarily see all things in the room where their physical body is lying, and further, you seek to explain this lack of evidence also on the 'strong mental and emotional state'of their spirit body such that it wouldn't take notice of discreetly placed symbols. And you don't say that this is just a possible explanation, you actually state clearly that this is what happens. Strange, because you don't give any actual evidence at all that your version is indeed what happens. it seems to be pure conjecture on your part, backed only by anecdotal evidence. Possible, of course. However, so is the idea that there is no such thing as the 'spirit' at all which moves away from the body in an OBE.
Why do you do this? After all, you accuse science of not taking on board alternative ideas. So, to be consistent, you should do the same, or you begin to look as if you are simply taking an extremely biased viewpoint. You should be looking actively for methods and evidence which are rigorous enough to support you own conjectures. Yet all you ever seem to do is deride science for its objective limitations, without actually suggesting any practical way that it might 'evolve' yet retain its objective viewpoint.
Interestingly, not all those who have a positive interest in NDEs and OBEs think like you and do undertake such veridical experiments (including, of course, the latest ones by Sam Parnia in his AWARE experiments, which again proved fruitless).
Indeed, his prolonged AWARE study conclusion has these words:
Thus, while it was not possible to absolutely prove the reality or meaning of patients’ experiences and claims of awareness, (due to the very low incidence (2 per cent) of explicit recall of visual awareness or so called OBE’s), it was impossible to disclaim them either and more work is needed in this area. Clearly, the recalled experience surrounding death now merits further genuine investigation without prejudice
with which I would entirely agree, noting particularly the last two words.