There are also cases where we can widely observe people being punished or having other problems from some behavior but not the behavior itself. Bribery or drug

There are also cases where we can widely observe people being punished or having other problems from some behavior but not the behavior itself. Bribery or drug use are two well studied examples. When you have a public awareness campaign that emphasizes how large the problem is people think "Gosh, I hardly ever see any one getting arrested for bribes or going to the hospital for using drugs, it must actually be safe if everyone is doing it" and the public awareness campaign backfires.