Is this rude?

I attended a professional development workshop today about brain-based math learning. This woman was on her computer the entire day. Well, the entire part of the day she was there, as she left early. At first I thought she was taking notes, but I soon realized she was spending her time online shopping. So my questions are 1) Why did she even come as she was not at all paying attention and 2)Is this rude, or just an acceptable modern use of time under the guise of “multi-tasking”?