Unless specifically stated, there is no 'right to privacy' inherent in any message board that you post on, just as there is no privacy guarantee on anything else on-line - every purchase you make on the internet unless specifically identified is recorded by the seller and likely sold on as 'database' information for other sellers - that is why email addresses fill up quickly with unsolicited offers - political parties and charities being the worst offenders! When breaches of truly confidential information do occur, there is very little legal recourse for the individuals and generally there remedy is a voluntary action by the entity that was breached as part of a PR effort to beg for your forgiveness. Data mining being a business that is huge in the connected world.
On your second paragraph, yes I agree, it is a minefield, but it has nothing to do with the turnstiles - it has to do with fandom. As soon as the competition is open to the public whether charged or not, it becomes an issue. But like hiring security to protect both the fans and the athletes during the competition, the schools do try to provide other levels of security as well. As with every other part of our society, it can never be perfect, but responsible fans, like responsible citizens, need to be part of that protection.