How to get door knockers to leave you alone

Breakfast 18/05/2017

SIDE NOTE: Photo above is a group of enthusiastic Mormons, not Jehovah's Witnesses.

Kara got a visit from a group of Jehovah's Witnesses yesterday, and door knockers are never a fun experience for her.  

"I'm the kind of person, that once they start talking to me I'll be there for an hour because I can just go 'no, I'm fine'."

I'll probably invite them in for a cup of tea, cause I feel bad

So, by and large she tries to hide when door-to-door people come knocking. 

Clint adds:

Not to dog their religion or anything, but don't come to my door with it.

We put a call out to you guys, how do you get people who turn up on your door who you don't have time to talk to, to leave you alone?