(CNN) -- "What goes up must come down" can be a deadly maxim when the thing that's coming down is a bullet.
"Celebratory gunfire" is all too common in many parts of the world, predominantly the Middle East, but also in parts of South Asia, the Balkans and Latin America. It's been done, in some cases, for hundreds of years and has become part of the culture.
Depending on which country you're in, shooting wildly into the air can be the favored way to mark a military victory, a public holiday, a wedding or a funeral.
One of the more iconic pieces of video to emerge during the fall of Tripoli surely must be the sight of CNN's Sara Sidner reporting -- or trying to report -- from outside Moammar Gadhafi's compound Tuesday. (Watch Sidner's report )
I was anchoring CNN's coverage at the time and could only shake my head as the cacophony of celebratory gunfire drowned out Sara's words and on several occasions prompted her and the team to seek the comparative shelter of a nearby wall. She was actually hit by a couple of shell casings as they left one particularly close AK-47 assault rifle.
The sheer amount of ammunition being fired into the air -- and the type of ammunition -- was staggering. Most were AK-47 rounds, but (what were they thinking?) some were anti-aircraft munitions.
Over my 30-plus years in journalism, I've covered my share of wars and conflicts and heard plenty of "celebratory gunfire" in places like Iraq, Afghanistan, the West Bank and Gaza and, most recently, Libya.
There was plenty of it post-battle in B'ir al Ghanam this month as the rebels made their push to the coast. (My BackStory colleagues tell me they chuckled when they heard me on tape mutter under my breath, "This is just unnecessary.")
But I have to say I'd not seen anti-aircraft "celebratory gunfire" before this conflict. And the volume of fire near Sara and the team was something to behold. Clearly, the rebels must have thought they had no further need for their bullets.
And I noted that several of the rebels, including one operating one of those anti-aircraft guns, might technically have been "shooting into the air," but only just. The anti-aircraft gun seemed to be pointed at an angle that would have made anyone on the third floor of a building in its line of fire want to don some body armor.
I have many memories of "celebratory gunfire." One is of a groom at a wedding in Amman, Jordan, who fired his pistol into the air outside a hotel to show his presumed joy at getting hitched.
And then there was the time in Gaza when gunmen escorting the body of a Hamas leader at his funeral fired hundreds of rounds into the air. After one of his (very hot) shell casings hit my arm, he helpfully reassured me I was safer standing alongside him because "no one shoots straight up, and when the bullet from my gun comes down, it won't be near us."
The problem is, it's often near someone, who might be up to a mile away. I covered the funeral of Yasser Arafat in 2005 and was thankful to be under a concrete balcony as his mourners unleashed a barrage of bullets into the air. Palestinian officials later told us nine people had been hurt by those bullets returning to earth, one critically.
One man made me leap when he let loose about 2 feet behind me. I looked at him and asked, "Why?" His reply? A cheerful "No problem! No problem!" and he fired one more burst to reiterate his point.
There are plenty of examples of people being wounded, or even killed, as a result of someone else deciding to show joy or sadness by pointing a gun skyward.
The U.S. Centers for Disease Control and Prevention looked at the dangers of falling bullets during New Year celebrations in Puerto Rico in 2003-04. Nineteen people were hurt and one was killed over a two-day period.
A falling bullet, according to a study by doctors in Los Angeles, can reach speeds of 300 feet per second -- it takes about 170 feet per second to penetrate skin, 200 feet per second to penetrate the skull.
And, when you think about it, if you're hit by a falling bullet, it's more likely to be fatal because it's probably going to land on the top of your head.