"Heads up!" It’s a phrase often hollered when it is too late to react to whatever is about to hit you, often squarely on your head.

If taken literally -- many of us respond by doing the exact opposite -- the phrase can result in a worse injury than if no one says anything at all.  And although the warning may not always provide enough time to dodge the bullet, so to speak, it does serve as a cautionary reminder of the rules of liability in situations when we tend to hear it most: at sporting events.

Take baseball.  It's America's favorite pastime.  The smell of an oiled mitt. The ballpark frank. Overpriced cold beverages. And a chorus of "Take Me Out to the Ballgame" during the seventh inning stretch.  All are etched into our nation's sporting memory.  Which is why millions of fans flock to stadiums to experience the action in person.

Baseball, however, is a dangerous sport.  Balls spray foul, bats break and fly into the stands, and players dive into the crowd to catch what hitters hit.  And spectators want to sit as close to the field as possible.

The result is inevitable: spectators get injured.

Other sports are much the same way. Hockey, soccer, basketball, football: all can incidentally cause serious injury to fans.

The real question is, "When an injury occurs, who is responsible?"

As with every legal question, the real answer is, "It depends."  But, practically speaking?

You are responsible.

An owner of an arena or stadium owes a duty to each patron to operate the premises with reasonable care.  In the context of sporting events, this duty is defined as a "limited duty."  Spectators are thought to assume ordinary and foreseeable risks inherent to the sport, such as flying pucks, balls, and broken bats, while owners are required to protect spectators in areas where these risks are most dangerous and most likely to occur, such as behind home plate or behind the goal. This is why baseball stadiums and hockey rinks feature netting in some places and not others.

Moreover, although fellow fans may heed a warning call, none is required.  The risk of injury from objects leaving the field or rink is considered obvious, and spectators are presumed to have known that this condition existed before attending the game.

Recently, a young girl's fingers were crushed at a baseball game when a bat broke and a fragment of it curved around the protective netting and hit her hands.  In court, her family argued that the owner of the stadium was negligent because the net was insufficiently long and there were no warnings about the possibility of projectiles leaving the field.

 The court ruled that the owner was not responsible because the net protected the most dangerous area of the stands and because the risk of a broken bat entering the stands was well-known.

Although one can't help but feel bad for the young girl, the court's holding comports with practical reality and common sense.  The law must balance fan safety with the tradition and allure of attending a live sport.

Baseball patrons want to be involved with the game in an intimate way, and many hope to collect a souvenir from the field, like a baseball. Fans want to be as "close to the play" as possible, without the visual obstruction of a net or screen.  We not only know about the risk of being in the stands. Often, we welcome it.

Further, although owners are not required to give warnings, most do.  Just listen to the loudspeaker at the beginning of a game, or read the message on the "Jumbo-Tron," or read the fine print language on the back of your ticket.

Finally, consider the practical effect of requiring individual warnings for each spectator. Patrons would quickly become fed-up with ticket sellers warning them that, in choosing to enter the park, they could be hit by a flying ball or puck. Retorts such as, "I know" or "duuuh," or much worse, would fast develop as frustrated fans waited to enter the park.

This proves a point: we do know of the risks involved, and we welcome them as part of "going to the game."

As with all areas of the law, there are exceptions, of course.  Fans assume ordinary risks, not extraordinary ones. For example, if an act by a player is intentional, we don't say that it is part of the game. Such is the case when an outfielder charges the stands and attacks a heckler, or in the all too memorable event at The Palace, in 2004, when Indiana Pacer players entered the seating area to fight unruly Piston fans.

These risks, unlike an errant ball or puck, are not assumed when attending, and fans often are successful in seeking compensation for injuries in such cases.

The circumstances in which the injury occurs also play a role in whether it is ordinary and reasonably anticipated. Consider the difference between a fan hit by a baseball in the bleachers, and a fan hit by a baseball while ordering food away from the field at a concessions stand.  The latter is more likely to recover for his injuries because one does not expect such an injury to occur.

Likewise, some courts have distinguished between injuries suffered during warm-ups and those suffered during regulation play.  Again, injuries incurred during warm-up are more likely recoverable because fans are less likely to expect them to happen.

So, the next time you're at a ballgame, instead of using your head to stop a ball, use your head to realize that a projectile might be heading your way.  Bring a mitt.  Order a hot dog or two.  Enjoy the game.