Are you changing your baby’s diapers on your fold-out tray for fellow airline passengers to see – and smell? Think nothing of putting your bare feet on the headrest in front of you? Making already beleaguered flight attendants pick up after you by throwing trash everywhere?

You’d better smile and say, “Cheese,” because some angry passengers and flight attendants might be “Passenger Shaming” your images on Instagram, Twitter and Facebook.

Created last year by “Sassy Stew,” who identifies herself on her blog Rants of a Sassy Stew as a "former cop, paramedic, stay at home mom and know-it-all doing this flight attendant thing," Passenger Shaming has over 150,000 likes on it's Facebook page, 153,000 followers on Instagram and almost 11,000 followers on Twitter.

Self-described on Instagram as “Photos of a--holes taken by anonymous flight attendants and passengers from all over the world,” Passenger Shaming is evidence that, in a post-Emily Post world where standards of basic manners and etiquette seem to have eluded many, people are taking matters into their own hands -- and smartphone cameras.

“Dirty diapers in seat back pockets are always a fun surprise!” reads one tweet. “Just some galley push-ups, no big whoop!” reads another, accompanied by an image of a man in jeans doing push-ups. The sites are abound in photos of bare feet propped up on seats and peeking through the armrests of passengers in front of them, making Passenger Shaming a foot fetishist's dream.

Earlier this month, the thorny issues of airline etiquette were thrust into the public eye as passengers fought over reclining seats and Knee Defenders, resulting in diverted flights and ruined vacations. But the passengers-behaving-badly images show that just because air marshals aren’t called to intervene doesn’t mean that people aren’t annoying one another daily in the unfriendly skies.

One could argue that taking pictures of unsuspecting passengers -- even rude ones -- and plastering them all over social media is in itself rude. But perhaps not as rude as comedian Marc Maron’s finding himself seated next to former GOP Chairman Ken Mehlman on a plane and live-tweeting his reaction, which included a photo of him exposing a nipple.

"Embarrassing another person is a breach of etiquette," said Patricia Napier-Fitzpatrick of The Etiquette School of New York to International Business Times. "So certainly 'Passenger Shaming' is rude. In fact, it is considered more rude than the act they are shaming. Perhaps it would be better to quietly ask a person to refrain from what he/she is doing. Or better still, ask a flight attendant to tell the person that what he/she is doing is offensive, annoying the other passengers or is inconsiderate."

It's too soon to tell if public shaming on social media is going to improve passenger behavior on planes -- it does seem like it has the potential to further erode etiquette standards. At least one shamed passenger is taking it in stride, though:  Writes shamed passenger "Mel" on Sept. 17 in a message retweeted by Passenger Shaming: “My sister found me being shamed! Hilarious!”