Legal sports wagering in the United States keeps expanding as the NCAA basketball tournaments approach, but the industry’s main trade group says a new wave of prediction market advertising could complicate oversight and weaken consumer protections. Fresh estimates from the American Gaming Association (AGA) show Americans are on track to legally bet about $3.3 billion on the NCAA Division I Women’s and Men’s Basketball Tournaments this year. The total would represent a 54% jump compared with wagering levels just three years ago, showcasing how quickly regulated sportsbooks have become part of the country’s sports culture during one of the busiest stretches on the calendar.…