Dog

I had a very strange encounter in the bank this morning. It went something like this...
I am standing at the glass door that is the entrance of the bank. There is a lady employee sitting directly opposite me, some three meters away and behind her desk. I gesture that I would like to come in. She looks puzzled. I point to the door handle because it is locked. She nods to affirm that she has understood my request. She makes angry stabbing motions in my direction with her index finger. She wants me to ring the doorbell? She stabs again. I ring the bell like a Pavlov dog. She presses a button on her desk and the door opens. I walk in, say good morning then politely ask why she had wanted me to ring the doorbell?

"Well, that's how we know you are there," she said.

Am I missing something here?