However once the impact of sunscreen is researched and it comes out positive you still need to convince people that applying sunscreen is a good idea. Just telling the information doesn't work that well. Demonstration like the one mentioned is better.
Again: Science changes; emotions do not; the job of public health comms is to generate emotions that roughly match science; but then science changes again, but the emotions do not.
The net result is that everyone's fear-compass is randomly pointing to findings from fifty years ago, which, incidentally, is why my last roommate couldn't cook.
The 31yo rock climber was terrified of salt. Why? His father had had a heart condition --- in nineties.
There are few things that could have brought the poor man more joy than ruining his dinner every night, which likely had the opposite effect than intended.
It's easy to spam links on this topic -- I went searching for this excellent summary:
https://www.nytimes.com/2012/06/03/opinion/sunday/we-only-th...
And found these two as well; I'm sure you can dig up plenty more
https://archive.nytimes.com/well.blogs.nytimes.com/2016/05/2...
https://www.nytimes.com/2011/05/04/health/research/04salt.ht...
You still have to communicate what you're assigned and, yes, the better you do your job, the worse the next person will have it, when (not if) the science changes.
Such is life.