Generally this is terrible advice, as others have stated.
However, if the fellow you are talking about uses a specific primer/powder/case/bullet all the time and knows what he is doing, he could get away with it safely.
What the hell am I talking about you might say??
Well, I know for a fact that I can take a .270 win case, fill it to overflowing with IMR 4831, shake off the excess, seat any 130 - 140 grain bullet on this charge, and I'll be safe and within published load data (admittedly older, not so "lawyerized" data).
So, if the fellow you were talking about happens to know for a fact that his load is safe, then he's basically just being tricky when he explained his reloading method to you, and left out the fact that his load is much less random than he makes it sound.