Let's see:
You are using the IP for your own purposes but...
...you don't own the IP...
...you've not bought the IP...
...the IP is not on public domain...
...you've not been given permission to use the IP and..
...you've not asked for permission to use the IP.

What exactly do you call this then if not "ripping off"?

Oh, and if that doesn't stick, replace "IP" for "car":

You are using a Car for your own purposes but...
...you don't own the Car...
...you've not bought the Car...
...the Car is not on public domain...
...you've not been given permission to use the Car and..
...you've not asked for permission to use the Car.

So I'm NOT ripping off a car under this scenerio?