how rude!

My roommate told me that her former roommate was coming over to visit her tonight. Sure enough, about 30 minutes ago I heard the doorbell ring and my roommate went to get the door. Her friend came in, sat down on the couch, and continued talking on her cell phone for the next 25 minutes, completely ignoring my roommate. I thought this was extremely rude. Either hang up the phone and continue that conversation later, or else sit outside (or maybe in your car, so you don't freeze to death) until you've finished talking. Is that too much to ask?