Right now, there is no evidence that regular use of sunscreen protects against melanoma. There is a bit of research to show that it protects against other skin cancers...but really, melanoma is the big one to worry about.
We use sunscreen if we have to be out in peak UV hours, but try to stay away from the chemical sunscreens and use zinc oxide/titanium dioxide based. I have had a hard time finding a spray or stick in that form, though. I don't use any sunscreen when they are babies--I use more clothing, coverage from sling, hats, etc.
But really, since there is no evidence that sunscreen is doing any disease prevention, I still think the best approach is to go out in non-peak hours, stay in shade (helps a little), wear more clothes/hats (personally I can be cool enough in longer sleeves if it is a flowy cotton shirt, and my kids wear longer shorts). Even slathered with sunscreen, I don't feel great about my kids being out in minimal clothing at noon in the summer. I need to check into the UPF clothing. We had some bathing suits like that, but unless they have changed, that material is very warm to wear--it was only tolerable in and around the water.
But yeah, ITA that saying "we will go outside after we put on clothes/hat/sunscreen is the way to go. Safety issue.