If they're the only ones trespassing, sure, arrest them. But otherwise let's keep the courts for the actual criminals.
And, by the way, let's not overestimate the alleged sanctity of journalism: they are humans too, as any of us, and there are numerous examples of journalists distorting facts for variety of reasons, starting from personal beliefs, and ending with bribes.
It’s not clear that this is the case in Canada, and your reference of a clearly American example doesn’t really clear that up.
[0]https://news.vice.com/en_ca/article/3kp7n3/canada-passes-law...
In my mind, they should arrest him, examine the evidence (gun from my pocket, pizza slices from my bag, camera from the journalist). I should then receive my 5-to-10. He should receive a pulitzer.
But at that time, we should both be arrested. Police will not sentence him or me. Courts will do that (sentence or release).
Justice is served in courts. Police should just stick to the basics: Trespass = arrest. Rob = arrest.
Irrespective of whether the guy/lady/etc. is a journalist, baker, etc.
Unauthorized entry is an actual crime. If you leave your front door unlocked and I enter your hallway just to admire your collection of shoes for a moment or two, I'm committing a crime.
That's the only way you can hope to obtain "retroactive authorization to have been there" from the property owners. (I.e. they have the charges dropped.)
You're likely not going to get that from the property owners if you side with the trespassers; then you're as good as one of them as far as they are concerned.
He should be processed by the system, and let the court of law judge him.
It's Canada we're talking about, he will have a fair trial, it's not Turkey where he would have already been imprisoned/tortured/"suicide-ed".