Last week on the Breakaway, my 15 year old son was able to use the fitness center each day with no issue. He is serious about his workouts and treats the equipment and facilities with respect. He was never asked to prove his age or scan his card. I don't feel that he looks older than his age.
Other groups of teens attempted to use the fitness center while he was there and the staff quickly kicked them out as they were obviously younger than 16 and messing around with the equipment.