For spectators at professional sporting events, there is a fine line between creating an intimidating home atmosphere and bringing the proceedings into disrepute, but common sense dictates where that divide lies.
Cheering at the top of one's lungs and heckling the opposition are customary and acceptable for fans, while actions or words that could pose harm to the well-being of players and other fans certainly have no place in any athletic arena.
And yet, there is a contingent of supporters at a specific venue who have been getting away with proverbial murder for years on end and escaping punishment at every turn.
This group was front and center once again this week in Mexico's scoreless draw with Costa Rica at the Azteca in a World Cup qualifier on Tuesday.
The Azteca has offered one of the most evident home field advantages in all of world football, and the reason goes beyond just the high altitude in Mexico City.
While Mexico always has been regarded as one of CONCACAF's most formidable footballing nations, El Tri's dominance in its national stadium - it has lost just one World Cup qualifier in four decades at the Azteca, falling to Costa Rica in 2001 - stems from the hostile supporters who create an unwelcome atmosphere for opponents.
Mexican fans at the Azteca are renowned not only for hurling verbal jibes at opposing players, but also hurling various objects onto the pitch. No item is deemed out of bounds for ammunition as batteries, coins and even bags of urine are consistently cast at visiting players and fans.
Tuesday night was no exception. With Mexico preparing to defend a corner kick from Costa Rica roughly 10 minutes from time, the fans at the Azteca began catapulting plastic bottles of liquid at Bryan Ruiz at the corner flag. The Fulham striker halted his preparation to catch the attention of referee Mark Geiger, who in turn notified the fourth official.
Ruiz attempted to deliver the dead ball into the box shortly after, but that was made impossible as more debris rained down from the terraces. The 27-year- old gestured toward Geiger once more, hoping the official would take some sort of action.
Multiple Mexican players protested what they believed to be an attempt by Ruiz to waste time in a bid to preserve the scoreline and a valuable road point for Costa Rica, failing to realize that their remonstrations held little water given the fact that their own fans were the ones causing the extended delay.
Fortunately, Ruiz and his teammates left the Azteca unscathed, but that does not erase the bigger issue at hand. Supporters endangering the safety of players is unacceptable and cannot be tolerated, and yet a blind eye is being turned despite years of atrocious behavior from a faction of Mexican fans.
Perhaps CONCACAF should take notes from UEFA, its European counterpart, which has displayed swift and justified punishments in dealing with such occurrences.
While European football has been consumed with a racism problem in recent years, the continent is not immune or unfamiliar with incidents that have become synonymous with the Azteca.
On April 12, 2005, AC Milan was facing local rival Inter Milan in the second leg of their Champions League quarterfinal tie. AC Milan entered the contest leading by one goal on aggregate and after Esteban Cambiasso had a goal called back for Julio Cruz's foul on AC Milan goalkeeper Dida in the build-up, Inter's fans erupted by hurling various objects onto the pitch. The incident quickly escalated and culminated with Dida being struck on a shoulder with a lit flare.
Play was halted and resumed following a 30-minute hiatus, but the match eventually was abandoned around the 75-minute mark when debris continued to find its way onto the pitch.
UEFA awarded AC Milan a 3-0 victory in the second leg to oust Inter from the competition, but the punishment did not end there. The Nerazzurri were fined over $260,000 and ordered to play their first four Champions League matches of the 2005-06 season behind closed doors.
This precedent has gone unnoticed by CONCACAF despite a pattern of projectiles flying from the Azteca stands.
The fact that no Costa Rican players were struck directly by any objects and the sealed plastic bottles do not pose the same danger as a lit flare are not adequate defenses for the Mexican national team escaping discipline. In fact, Mexico essentially was rewarded for the poor behavior of its fans when the fourth official indicated seven minutes of added time. Seven!
Let that be a lesson to fans around the world: If your team is involved in a close match down the stretch and you have hopes of them pulling out the victory, just start throwing things onto the field! You'll be awarded with seven minutes of added time and you won't be punished.
CONCACAF has an opportunity to take a stand and be proactive in protecting its players by levying a punishment on Mexico that is in line with what UEFA handed down to Inter Milan eight years ago. Why wait until a player gets injured from a projectile before taking action?
Do you think Mexico's supporters will be more well-behaved if El Tri was docked points in the Hexagonal? Do you think they'll think twice about catapulting items onto the pitch after Mexico is forced to play its final two Hexagonal matches behind closed doors?
Mexico has habitually toed the line between creating an intimidating home atmosphere and endangering the safety of players. Perhaps a punishment from CONCACAF wouldn't have the desired effect to affect change in Mexico's supporters, but the governing body's lack of action is appalling.