Am I wrong in thinking this is ridiculous?

My workplace is supposed to be open 7-7. We don't have the staffing for it and we close early every night. Management won't update the sign out front.

Every night, while I clean the garage, dozens of people knock on the door. I don't answer it because it's locked and we're closed.

I got reprimanded by a manager tonight because a customer was pissed at me for not answering it.

Why do we lock the door if they just want me to open it up anyway? In that case, it should stay unlocked. The sign out front needs to be updated. I can't answer the door 20 times every night while I'm trying to clean the garage before my shift ends.

I'm thinking about just telling that manager that if anyone comes to the door, I'll just go get him so he can answer it 20 times per night.