[Gogar]

Just answer the door.

Don't say a word.
Stand there.
Stand there some more.
Don't answer a question.
Don't make a sound.
Stand.
Wait.
Quiet.
Maybe a blank stare.
Dead quiet. Questions? no. Words? no. Just silence and a blank stare into space.

It will take less than a minute and will give you total control of your doorstep, and maybe a laugh.