Im new here and just got a premium deal recently too

Now my girlfriend have started to play as well.
Yesterday, she logged in with her acc from the same PC/IP Im using.
I am wondering if that is an issue of multing?
We dont share any games or so. But could we?
If not regular games where you get points etc is it possible to play without points involved?
I dont know if private games include points.
Also if doing regular games vs other people, no illegal teaming would occur obviously, unless team games ^^
Please clarfiy the rules for me.
We both want to play here. Would be nice if we could play against each other too.
I have read the rules. But Im not sure how exactly CC detects multis. Is it purely technical? Ie looking into IPs and scoring? Or do they actually investigate the actual games and players involved?