Is this rude?

I was with a person who shall remain nameless. She had a phonecall from a mutual aquaintance and she put them on speakerphone. She did not tell them I was there. This is not what she ususally does when someone calls. I kept thinking she was going to tell them I was there but she never did. It made me uncomfortable. Maybe I am just behind the times and this is common for people to do nowadays. (I don't have a phone)