Its an elite invite-only boarding school, so you're unlikely to know anybody when you arrive. But also, it tends to clump people together by family cough bloodline cough and common interests, so the theory is you'll make friends more quickly when you're coughWEAZEcough segregated into like-minded groups gaspGAGchoke fuck me its really bad the more I think about it, isn't it?

A bit more seriously, its not crazy unusual for schools and unis to organize people into fraternities and clubs and houses and other social units early on in your college career. Then you tend to just end up with these people as your friends by virtue of proximity. By applying a certain degree of blind randomness, or by sorting via interest and passion rather than letting people congeal based on their own historical biases, you get a better mix of students than you would if everyone just clumped by who they knew or thought they'd like.

The system doesn't have to be modern phrenology.