Some people know just enough to be dangerous.

For instance, an anecdote:

A nearby local hardware store put up a sign in 2017 and now this year, in front of the welding equipment, that says “WELDING GOGGLES DO NOT PROTECT EYES AGAINST THE SUN”

Now if they didn’t block uv from the sun, then they wouldn’t block uv from your welding arc.

BUT I 100% stand by their choice to put the sign up.

Because you need a certain shade or darker, and they sell a lot of different shades for different welding applications, including the safety tints people might want if they’re nearby and catch the occasional reflection.

And some people know enough to know welding arc = UV, sun = uv, and don’t stop to think about intensity.

In fact, in 2017, I knew someone who tried to use a #3 lense to look at the total eclipse, and as soon as the moon cleared moved enough for the sun to peek back, he deeply regretted not using a darker shade. Now has a weird spot in his vision that isn’t quite right.