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Tennis champion Roger Federer understands this very real risk well, which explains why he was none too pleased last year when a young fan stormed the court at the French Open hoping to snap a selfie with him. Federer was unharmed, but he asked for immediate action from the French Open organizers.
"Obviously, not one second I'm happy about it," he said, per the New York Times. "Normally I only speak on behalf of myself, but in this situation, I think I can speak on behalf of all the players, that that's where you do your job. That's where you want to feel safe. And so clearly I'm not happy about it. But nothing happened. So I'm relieved, but clearly it wasn't a nice situation to be in."
Adam Levine had an uncomfortable moment of his own onstage when a fan rushed the stage and grabbed hold of him mid-song.
"She ran full speed at me, and I was, you know, singing," the Maroon 5 rocker said in an interview with Today's Carson Daly. "I was not aware of her. She was on me, the next thing I knew."
Someone off-camera asked where was Adam's security when this woman was rushing the stage. "Good question," he said, clearly unhappy with what happened.
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Back in 2013, Justin Bieber had a scary experience in Dubai when a fan attempted to grab hi while onstage and accidentally knocked down a huge piano in the process. A man claimed to be the one who rushed the stage called in to Virgin Radio Dubai to extend an anonymous apology to the Biebers. "I want to say sorry and if Justin can hear me, I didn't mean to scare him," they said. "I'm a true Belieber."
While any type of celebrity ambush has the potential to be dangerous, there are some occasions the individual behind the attack goes in with obvious intent to cause harm. Back in 1993, tennis player Monica Seles was stabbed between her shoulder blades by a deranged man in between matches at the Citizen Cup in Hamburg, Germany.
Security was able to intervene before the man could inflict further damage, but Seles was out of the game for two years. Although she eventually recovered physically and returned to the sport, she struggled emotionally with the trauma of what happened for many years. She wrote candidly about how the incident changed her life in her 2010 memoir Getting a Grip: On My Body, My Mind My Self.