Don't you DARE - What are good examples of common sense approaches that were found to be ineffective or even counterproductive?

In his book ‘Redirect’, social psychologist Timothy D. Wilson mentions DARE, which stands for Drug Abuse Resistance Education, and which is used in 75% of all US school districts and has spread to 40 countries, including Germany. My wife mentioned policemen visiting her school, giving talks intended to prevent students from using drugs. To me the whole DARE concept makes a lot of sense and I find it puzzling that numerous studies have shown that the DARE approach is rather ineffective. Perhaps in even counterproductive in some parts. Billions and billions of funds are still being spent on DARE.

Instead of DARE, Wilson recommends the LST approach (life skills training), which focuses on self-management and social skills including dealing with peer pressure.

Do you know of any other common sense approaches that turned out to be ineffective? Or that might turn out to be ineffective if scientific studies were conducted to measure their effectiveness?

What is your personal experience with DARE?