Please tell me how to politely refuse people who come to use the restroom in an office building. Thank you.

In fact, people have three urgent needs. It would be very embarrassing if they cannot be solved in a more urgent situation. I have personal experience. . . . But it doesn't make sense to not let people use it, but considering that people can come and go casually in the office building, it's a bit wrong, especially because it doesn't give a good impression to customers. Slogans can include "There is a vicious dog inside" and "Please take away the things you left behind." The appearance of the slogans and placards should be more cartoony or three-dimensional, and should not be as "righteous" as the warning signs.