It is an open secret that if your parents are alums of and/or have given enough money to, say, Yale (the Bushes, for example) or Harvard or Stanford or Cornell or whatever, you will be accepted much more easily than if not. It's not clear how big this advantage is, but it's well known enough that people have a term for these students ("legacies") and from time to time they complain about them.

http://www.nytimes.com/2011/11/06/education/edlife/being-a-legacy-has-its-burden.html?pagewanted=all

https://en.wikipedia.org/wiki/Legacy_preferences

Does BYU do this for big donors or for alums more generally? I have no problem with it personally, I'm just genuinely curious.