Analysis: we've seen many games and matches disrupted by spectators seeking to play a prank or make a protest

Spectators can become excessively and emotionally absorbed with sports events. This can often lead to supporters using physical force to interfere with live play, which can range from violent and uncontrolled acts of aggression to collective, pre-planned involvement in the sports arena.

There have been many recent instances of spectators interfering with live play and having an active role in disrupting the flow and trajectory of a competition and, quite often, the overall result. On the opening day of the 2021 Tour de France, a woman holding out a cardboard sign on the roadside between Brest and Landerneau caused dozens of riders to crash. According to the race's video coverage of the incident, the sign hit German rider Tony Martin who was cycling near the head of the pack. Martin fell, which led to cyclists falling en masse leaving bikes and bodies tangled in the road and the race being held up for several minutes. The spectator was later arrested, though Tour de France organisers have dropped a move to sue her.

In the Euro 2020 quarter-final between England and Denmark, a green laser pointer was shone by a spectator at Denmark goalkeeper Kasper Schmeichel before Harry Kane's crucial extra-time penalty. Schmeichel revealed that he told referee Danny Makkelie about the laser being pointed at him before the penalty, which Kane subsequently scored sending England to the semi-final. The English FA being fined €30,000 by UEFA for the incident will provide little comfort for Schmeichel and the Danish fans who were knocked out of the competition because of that penalty.

Interferences at sports events can also be collective and in many cases, they are usually preplanned. In March 2019, tennis balls rained down onto the Aviva Stadium pitch as Irish soccer fans threw them in the 33rd minute of the Republic of Ireland's Euro 2020 qualifier against Georgia. This was a pre-planned action to demonstrate fans' disgust with plans for John Delaney to vacate his chief executive role for a newly created executive vice-president position in the wake of revelations around a 'bridging loan' he paid to the FAI.

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From RTÉ Sport, the pundits were at odds over the tennis ball protest during the first half of the Republic of Ireland's qualifier against Georgia.

Although the incident forced the match to be delayed by four minutes, it was swiftly following by a winning goal by Conor Hourihane. The FAI were later hit with a €10,000 fine for the protest. In the same month, the Football Association of Montenegro were fined €20,000 for charges related to the setting off of fireworks, the throwing of objects and crowd disturbances and the blocking of stairways at the Gradski Stadion.

Collective spectator interference is not always rooted in anger or malice but can also develop as a celebratory expression and have positive connotations. The Teddy Bear Toss is a common event among minor league ice hockey teams across North America and Canada and involves fans throwing stuffed animals onto the rink. These are then collected and donated to charity. In 2019, Pennsylvania ice hockey team the Hershey Bears set a new world record after more than 45,000 bears and other stuffed animals invaded their rink during a game.

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From PennLive, Hershey Bears' fans toss 45,650 teddy bears and stuffed animals onto the ice in 2019

A spectator’s temperament, personality and/or current state of mind influences the likelihood that they may be motivated to disrupt a live sporting event. Fr Neil Horan is a serial offender when it comes to forcibly interfering with major sporting competitions. Also known as 'The Dancing Priest’, Horan is of the religious belief that the end of the world is near and has used events such as the Olympics and Formula One Grand Prix as his platform for garnering attention.

In July 2003, Horan tried to disrupt the British Grand Prix at Silverstone Circuit when he ran across to one of the fastest sections of the track, the Hangar Straight, forcing some cars to take evasive action and swerve out of his way. Millions of TV viewers worldwide watched as Horan dressed in a kilt ran on to the track waving religious placards. He was eventually wrestled to the ground by a marshall and arrested.

At the 2004 Olympics, Horan obstructed Brazilian athlete Vanderlei de Lima in the men's marathon by pushing him into the crowd. This unwanted interaction with six kilometres left in the race caused De Lima to lose his leading position and approximately 20 seconds off his time, allowing Italian Stefano Baldini to win gold. Following the incident, the family of the non-practicing priest sought to apologise personally to de Lima and to the people of Brazil for the harm caused.

A short history of Formula 1 track invasions by spectators

Tennis has been marred by numerous instances of spectators infiltrating the court. In 2009, Roger Federer was confronted by an intruder midway through his French Open final victory over Robin Söderling. Perhaps the most shocking interference was when world number one Monica Seles was attacked by a German spectator at a tournament in Hamburg in 1993. An obsessed fan of Steffi Graf, the spectator jabbed a 9-inch long knife at Seles’ back. The attacker said he had no desire to kill Seles, but only wanted to injure her just long enough to let Graf regain the No. 1 ranking. Seles spent two years recovering from the stabbing but she was never quite the fearless player she had been prior to the shocking incident.

Streakers have become an unsightly common phenomenon in sport. The first instance of stripping off one’s clothes and running around naked in international sport was during a rugby union friendly between England and France at Twickenham in 1974. Michael O’Brien had a bet with his friends that if he shed his clothes, socks included, and then ran across and touched the stands on the far side, he would win £10. O'Brien would have to use his winnings to pay a fine of £10 for "insulting behaviour", but he was at least allowed back into Twickenham to catch the end of the match. Photographer Ian Bradshaw captured the shot of the naked young man being corralled off the field by a trio of policemen, won numerous awards for his photo.

Spectators have a relatively simple role: to attend sporting events and support their chosen team or athlete. Of course, the nature of sport means that things can get heated and fans are as excitable as anybody else involve. But physically interfering with a contest is the lowest form of spectator behaviour.

The views expressed here are those of the author and do not represent or reflect the views of RTÉ