What if a person at the door is an apostate?
We have to use discernment and insight at the door.
As Brother Mike @Mike047 said,
"apostates are not likely to wear badges"
Simply because a person at the door raises a controversial topic or their words/tone sound "apostate", does not make them a true former Witness who turned traitor.
Sometimes a householder(HH) who has never been a Witness has heard rumors or myths from relatives, friends, internet, about certain "hot" issues involving JWs, such as child abuse, the blood issue, etc. And their personal conscience or sense of justice may cause them to be frustrated or even angry at us! And therefore they may act and speak "like" an apostate, but they are not.
Jehovah understands that some unbelievers will hear rumors/myths/lies and become upset or angry with His people or even Him! Yet Jehovah is compassionately reaching out to such ones through us in the ministry.
So here are a few suggestions to help us try and determine if the HH is a real apostate or not:
If the HH raises a controversial topic or their words/tone sound "apostate".
And if you are concerned the HH might be an apostate, then...
ask kind but discerning questions like, "Have you ever been to a Kingdom Hall?", "Have you attended any meetings or assemblies of Jehovah's Witnesses?"
Questions similar to these might draw out the person to express how he/she used to go to meetings or that he/she used to be a JW. We can gain insight from their answers.
If the HH is being evasive/suspicious in his/her answers, then we can...
use a more penetrating question to expose the HH's motives
Just as Jesus did with opposers in his day: "...the chief priests and the elders of the people came up to (Jesus) while he was teaching and said: "By what authority do you do these things? And who gave you this authority?” In reply Jesus said to them: “I will also ask you one thing. If you tell me, then I will also tell you..."
If our penetrating questions reveals in some way that the HH used to be a former Witness, then we can politely end the conversation and leave like Sister Hannah @TheKid23 mentioned she did in 1 of her posts above.
But If the HH's answers seem genuine and indicate that he/she has never been a Witness, then we can...
decide how we want to respond to their "hot" questions.
If we give a kind, gentle answer and the HH seems to be a little more responsive or at least calms down from their initial "attacking" words, then we may be able to continue giving a witness.
BUT if the person still seems agitated/upset/angry. we can use good judgement/discernment to determine whether it may be better to politely take our leave even though the HH is not an apostate, but to follow Jehovah's higher ways concerning any potential arguments, "Before the quarrel breaks out, take your leave" (Prov 17:14)