That won't prevent my maid from opening the door.
If I tell my maid in this way, I think she will open the door immediately without hesitation. (That's what I guess from her behaviour)
TAlking about common sense, I don't think this relates to her common sense. My maid's common sense comes out selectively on different occassions. Say, she has high intelligence when deleting her calling records in my home phone, telling all kinds of lies, etc. Bit when it comes to matters like opening the door to strangers, her common sense dissappears and she has records of letting strangers enter our house whenI was not around. The matter is: SHE HAS NO CONCERN FOR YOUR AFFAIRS.