I have a daughter of 13 years old, because she heard the beep of reminding people who didn't get on the bus when the Shanghai subway closed, so ......

There is a good side and a bad side. As the last one said, it's impolite, but I think it's cute for children to do so. But more importantly, you should see that your daughter is very caring and graceful, which is not easy to do at her age. This good habit will make her live in peace with others. I think it's best not to stop her.