College kids go out on Friday nights, have a few drinks, and decide they need a cigarette. They have been told that cigarettes can cause cancer. But no one bombards them with danger warnings about their visit to the tanning booth earlier in the day.
Skin cancer is a major health problem and a big share of the blame for that goes to indoor tanning. Despite knowing the health hazards, people still do it, and that includes many under age 18.