Utter rubbish, it might help slightly with getting your foot in the door, but that's it.
I reckon that getting your foot in the door is virtually 98% towards getting that job. I agree that nothing is the be all and end all, I'm merely trying to rationalise the apparent advantage of getting that foot in the door that the 'big' school guys are perceived to enjoy.
FWIW I trained unknown small school modular and work for a big name. But I am alone amongst the other cadets in the that respect.