Have you ever been to a game where there is an oddity - a person that runs across the field in the nude or wears some funny costume in order to get attention and later arrested? If so, do you think it affected the performance of the players?
I wouldn't say it affects the players in any way. They are professionals, and are used to having various things done to them in order to break their concentration, which very rarely work. If anything, I think it just makes them laugh, or get angry, depending on the situation, and life goes on.
For those of you that watch the NBA, a perfect example is when people behind the bench, or behind the backboard try to distract the players...never works.
I havent witnessed this personally, but have seen a few occurrences on televised sporting events. I think most professional athletes find this scenario assuming more times than none. The only time it may affect the game itself is if the person who disrupts the game attacks one of the players. I remember watching one baseball game where a fan attacked the first base coach, and the game was delayed for 30 minutes. This can become a huge distraction.