In my dojo we've a girl who only comes because her boyfriend does. She chatters through the class, flirts, squeaks (literally) and is generally a disruption. Sensei will demonstrate a technique that involves, say, a wrist grab. Then when she partners up she doesn't even know what she's supposed to be doing cause she hasn't paid attention. Not to mention the low cut sweats she wears those show almost her whole butt - crack-held thong included. It's distracting and annoying.
Our sempai however - she kicks ass and takes names. I enjoy having women on the mat who actually want to be there. I might pursue a friendship with them OUTSIDE the dojo but that has no bearing on INSIDE the dojo.