Well that´s normal of any sporting event , whether it be here in Europe or in The States . If I go to watch rugby in England ( 75,000 people ) or even the tennis at Wimbledon or rock concerts ... Queen with 250,000 people for example . I´m always careful but I´ve never had a problem .
Having said that , I got a letter a few days ago from my ex-neighbour . My house looked over a park and every June they hold a huge classical concert by the Royal Philharmonic Orchestra . You take your picnic there and enjoy the music . 2 years ago a guy was murdered right infront of the house I used to own . It was some stupid idiot , on drugs ,who was trying to steal one of the deckchairs of another person , he stabbed the innocent guy . He´s in prison now .
Those big occasions can lead to abnormal behaviour .