Manners - Old Fashioned in a Digital Age?

I remember my parents worked hard to instill good manners in my when I was little. Things like "don't talk with your mouth full", or "use please and thank you" were simple rules I was to live by. And what about the golden rule? Did you ever hear, "Do unto others as they would have them do unto you"? Today I had an experience that has me wondering how this applies to our current tech age.

As we waited in the check-out line the woman ahead of us was busily talking on her cell phone. She continued with her discussion during the transaction much to the irritation of the cashier trying to help her. She went through the line and failed to tell the cashier about the items under her cart and even when she was stopped, she didn't put her phone down. We have double conveyors at this particular store, so to bag my items I had to ask her to move. She was too busy on her phone to notice anyone around her. Now, I am assuming the call was not important because of a) the length of call b) all the smiling and laughter c) the fact that eventually she ended the call with "Oh, I should bag my groceries now". So, does this seem kinda rude to anyone else?

If you are wondering if she was young, she was older than me (I am in my 30s!). If you think teenagers are the only ones oblivious to their surroundings while engrossed in technology, you would be wrong. I rarely hear people complain about the middle age set being rude with their cell phones or PDAs, but I am sure we have all experienced the "loud talker" in mid conversation, or people busy on their cell and not driving responsibly. Of course movie theaters and doctors' offices alike have to remind patrons to turn off their phones out of respect for others. So where are the manners?

I assume this technology is too new for there to be a set standard of social guidelines or manners. Cell phones have only been widely used since I was in college. My parents never had to talk to me about the implications of "sexting" or when it is appropriate or not to use a cell phone in public. Since it bothered me so much today, now I am thinking about what I want to teach my children. Call me old fashioned, but I want to instill some manners in my kiddos.

I am curious. Have any of you talked to your children about technology and manners? What do you expect of others around you using their PDAs or computers?