I remember when first got online, I fell for every "make money online scheme." The experience thought me to subconsciously / automatically ignore them.
Rather than spend unnecessary resources on a technical solution or filter, lets inoculate them.
FAKE NEWS INOCULATION
Create more ridiculous rumors that can easily be debunked.
WhatsApp and other platforms can randomly spam their users with these lies and at the end of the message, write - its a joke, April fool or whatever.
With this, we'll get to nirvana in half the time, with 10% effort and resource.
I worry that would have the opposite effect - it would train people to look for that, then assume messages that _don't_ have it are real.
I could also imagine gamifying... tie the Report button to in-store credit or some kind of "debunker" badge, to reward people guessing that videos are hoaxes.
My dad used to drive me crazy forwarding hoaxes. But in his case, it was because he knew it will, and found it amusing. As he told me « I only forward you a 10th of what I receive ! »
We can try education but that will take at least a generation or two to take effect.