A bit off-topic, but you citing 17k as the population of Princeton "proper" is quite wrong. While it is true that Princeton Township and Princeton Borough were once different municipalities, they shared most resources and, importantly, a cultural identity and school system.
The distinction between Princeton "proper" and otherwise is not between the Township and Borough (which were legally joined for good several years ago), but between Princeton and Princeton Junction, West Windsor, Kingston, etc.
The population of Princeton is 25k+.
Anyway the moral of my story is that calling the township Princeton "proper" attempts to create a divide that the residents don't care for, and dismisses many of them as not being from the "real" Princeton.
Source: native of Princeton (specifically township, but I actually have no idea which of the borough or township my friends lived in) with a slight stick up his butt.