The nerve of some people

I work in a building that has a convenience store located on the first floor and run by a woman, named Emily, who is blind (on a good day she can slightly see large objects moving about).  When you walk into the store there is a sensor that beeps loudly so she knows when someone is coming in or going out-no matter where she is in the store.

Well today there was a little girl about 4 years old and her mom visiting one of my co-workers (I'm assuming this was her daughter and grand-daughter but I don't know for sure) and this little girl kept standing in the doorway of the store making the sensor go off so poor Emily didn't know if someone was in the store or not. 

Let me just say this is not what is irritating me-I can understand children really like to do things to figure out the cause and effect of the action.  What irritates me is the fact that this child was standing there and when Emily asked her to please move, she went and told her mommy (who was NOT paying attention to her child and was chatting with said co-worker on the other side of the atrium) that the lady told her that she couldn't stand by the store.  So she told her daughter "Oh you don't have to listen to her.  You can stand wherever you want...it's not like she can see you anyway" and off the little girl went to stand in the doorway again.

O   M  G!!  SERIOUSLY?!?!

I don't get it at all-why not take this as an opportunity to educate your child and teach your child compassion.

Oh, and yes I did say something to the little girl and let her know what the beeping was for and she seemed to understand and moved just a little bit so the beeping stopped.  I'm sure I pissed off the co-worker but I don't care.