2ip addresses on 1 comp?

I think if you have two cable providers, your cable modem has it's own ISP, not your comp. not sure.

Anyways I'm asking because my roomate wants a PP account, but I don't want to go through the hassle of getting flagged, or having my bonuses taken away. Obviously won't be colluding on just one comp. Anyone know if once I get her account set up and deposited into, if we will be in the clear when she signs in on my comp with her own ISP?