[wiether]

> If you have tattoos its entirely possible you'll actually be more careful in the sun by applying sunscreen.... but you also might be more prone to showing your ink off and therefore exposing a greater area of skin to the sun.

Knowing multiple tattoo artists, that's exactly what they observe from their customers : some are very careful about their skin exposure while other are doing the exact opposite.

They are not healthcare professionnal so they don't study skin cancers, but they can easily tell which one is which based on how the tattoo evolve year after year.

This could probably be the easiest factor to check.

Regarding the inks, since there's little to no regulation, even in the EU, and people tend to get tattooed when away from home, it could be much, much trickier.