Border Crossing Land and Air to get back into Canada

What to say at the Border

Land:
Refuse to disclose your vax status, refuse to download ArriveCan app.
The Border Guard will ask twice
They are literally powerless
They may direct you to a secondary examination
That is all they can do, direct you to park your vehicle

If so, ask "Am I being detained?" or "Why am I being detained?"
If you are being detained they have a duty to read your rights and put you in contact with a lawyer immediately. You will never get this far, they will give up since they have no power.

Re: the app say "I do not agree to the terms and conditions of the ArriveCan app.

At an airport:
Candian Border Services Officer will try but again, they have no authority
They will try to trick you to talk with Public Health

Say "Am I being referred for a customs examination or is this just to speak to Public Health?"
If it's just public health, then just decline and go home.

Now some places are using the Police to threaten to arrest if they do not download or speak to public health. Seems like they are more scary. But they also do not have the right.

If they say you must download the app and speak to public health, or be arrested, say "go ahead" and then start filming
once again they must inform you of why you are being detained
and read rights and put in contact with lawyer immediately.
The officer will start bumbling so have the camera on him. He has no authority
then ask "Am I free to leave or am I being detained?" you will be able to leave.