I would say that whether it is a myth or not - that many college coaches look for signs of it and most will try to avoid it.
Of course, if your son throws 95 with command of 3 pitches, they may not care if you move into the dorm with him.
(BTW, I'll stick to my view that it most definitely exists and that I have more examples than the one I cited above. Damaging? A reasonable argument could be made either way I suppose. Pervasive? I wouldn't know, but it is out there, no question).