When you are in a bathroom and some one knocks on the door, what is your response?

I can see Uber asked this about THREE YEARS AGO and even if I answered his question it would stall out again. So I hope I’m forgiven for asking it again.

ANYWAY, if they can come in I say, “Come in!” If they can’t I say, “Just a moment please!” and I sing it out because I’m talking through a closed door…..have you ever known someone who’s response is simply, “Yes?” Like…do you think I’m standing out here so I can have a conversation with you through a closed door, or what?