Highly biased opinion!

First, HYP, they all do that.  H and Y are traditional rivals.  Have you heard H and Y are rivals and P is still irrelevant?

Second, Y is the most liberal, P is the most conservative and H is in between.  H is arrogant and Y is more laid back and humble.  If you visit the campus then you will see the difference.

Third, look at matriculation rates as WXC501 cited, who is more insecure?

Forth, When H revokes EA, P follows and when H reinstates EA, P follows again.  Who lacks confidence?  Y stood regardless.  Y is confident and comfortable in whatever the place and does whatever it supposes to do.  It's P that lacks confidence.

Fifth, P's admission is most strange one among HYP and at least in our region, students choose H, Y and P in order, which confirms the cross-admission matriculation.