What about all the stuff "we" learnt in the IR, about multiple false glideslopes which exist above the real one, and on which the GS indicator indicates in reverse i.e. an UP indication actually means you have to go down?
That's why one should not intercept a GS other than as published, or if doing a
CDA then one needs to make sure the angle of descent is close enough to 3 degrees to ensure the instrument indication is well within limits for the last few miles.