When, if ever, it is okay to haze or prank new sailors, airmen, marines, or soldiers?

There's actually studies that show hazing is a good thing. Before an idiot comments: obviously it has to be within reason, a wood mallet to the chest is not within reason. However when hazing is done constructively, it makes the new person or people feel like they have actually been accepted into the group and without gritted teeth. That leads to more cohesive groups. The study I saw way back was specifically aimed at the civilian business sector, but the principles apply to any group.

SSG Carlos Madden The Picture is a Little Deceiving, It is Not New Sailors but Pollywogs becoming Shellbacks. Crossing the Equator in a Ship, No Matter what Navy, A Tradition. Is It "Hazing" Most Definitely, Is It Carried too Far, To Extremes Sometimes I'm sure it Happens. I will say I was not Beaten with a Shillaly (Whip Made with Cut Piece of Fire Hose) which Happened to Others Before Me Years Before. Yeah I was a Pollywog Until My Last Year. You Bet My Subordinates had a Great Deal of Fun Making Me a Shellback.

In my understanding, there is a VERY large difference between pranking and hazing.

Pranks are good-natured in intent, and are "equal opportunity," meaning that if I prank you, I should expect you to prank me back. Most pranks can also be "defeated" with proper attention to detail and/or cunning. (As a young PV2 RTO, my squad leader told me to ask the PSG for a PRC-E 7 (pronounced prick e-7, for those who don't know) ; I complied. I went to the PSG and told him that I was looking for a PRC-E 7, and my squad leader said the PSG would be a good place to check. My PSG laughed his butt off and told me to go send him my squad leader.) If the pranked Soldier laughs afterwards, or even DURING, there is a good chance it is a prank.

Hazing is demeaning in intent, and are "one way," meaning that there is always a defined hazer / hazing group and hazee / hazed group (even if that hazee "earns the right" to haze others in the future, (s)he will not be hazing the hazer). Hazing cannot be "defeated" it can only be complied with or refused (often with repercussions, even if the repercussions aren't official). If the hazed Soldier is not laughing, but rather ENDURING, there is a good chance it is hazing.

Is it OK to prank new Soldiers/squids/zoomies/coasties/marines/guardians of the galaxy? Absolutely, as long as it doesn't interfere with the mission. Collecting exhaust samples and checking for soft spots in the armor are rights of passage that no one I have ever met was offended by.

Is it OK to haze new Soldiers/squids/marines/zoomies/coasties/guradians of the galaxy? Never. Never ever. Never ever ever.

It goes too far, in my book, when it crosses the line from fun/funny to taxing, demeaning, or dangerous. If you send a Soldier to collect exhaust samples with a ziploc bag, it is funny. If you send a Soldier to collect exhaust samples with their mouth, it is demeaning and dangerous. If you send them for exhaust samples every single week, it is taxing and demeaning. If you send them for exhaust samples and they say "yeah, hah ha. Not falling for it" and you proceed to smoke them for failing to obey, it is demeaning. Etc.