False. I know of a few 'sons of' who didn't get in. Even when it wasn't open to the public, being a 'child of' didn't guarantee you a slot. The 10% figure would be about right. We had one out of 8 on my course in '91. Other courses had none. I think the total would have been 8-10 out of the 85(ish) of us.
Beyond that, what do you hope to achieve in this thread? Those that 'know', know the truth and won't have an opinion different to mine. Those that don't know will just sprout crap. You have the answer