Many companies have relaxed their social media policies in recent years. For one, more companies want their workers to be active on social media, and it may even be part of their job description. Some studies have even found that employees who use social media outperform those who don’t.

But sometimes employee social media usage gets out of hand—whether they’re using it at home or from their work computer. These situations can put companies in a prickly position, as they are forced to decide whether the social media blunder is severe enough to warrant termination.

Here’s a look at five common reasons people get fired for their social media usage along with real-life examples:

 1.    Badmouthing customers

A common reason employees’ social media usage gets them fired is they made a disparaging remark about a customer.  That’s how then-22-year-old waitress Ashley Johnson got herself canned from Brixx Wood Fired Pizza in North Carolina in 2010, according to the Charlotte Observer. Venting about customers who left a $5 tip, Johnson wrote on her personal Facebook page: “Thanks for eating at Brixx, you cheap piece of —- camper.”

Though Johnson’s Facebook page was private—meaning only her 100 or so friends could view it—her employer somehow found out about the comment and her manager terminated her within 48 hours. Brixx’s managers wouldn’t disclose how the company found out about the comment, but said that Johnson broke a couple of the policies in the employee agreement she signed when she was hired—including not badmouthing customers on social media.

“It was my own fault,” Johnson told the Observer at the time. “I did write the message. But I had no idea that something that, to me is very small, could result in my losing my job.”

2.    Making distasteful or derogatory comments

It’s not just employees that get in trouble; sometimes executives get in trouble, too.

Mahbod Moghadam, cofounder of online lyrics and literature annotation site Rap Genius, resigned from the company and its board of directors in 2014 after posting an annotated edition of a mass shooter’s 141-page memoir/manifesto on Rap Genius, according to Business Insider.

Elliott Rodger shot to death six people near the University of California, Santa Barbara, before killing himself. Rodger already had plenty of entitlement and hatred for women to express in the screed he left behind, but Moghadam apparently thought it was entertaining to pile on.

In one comment, which Moghadam later apologized for, he said the killer’s sister must have been “smokin hot.” Outrage over his comments led to his resignation.

“Were Mahbod’s annotations posted by a Rap Genius moderator, that person would cease to be an effective community leader and would have to step down,” Rap Genius cofounder and CEO Tom Lehman said in statement shared by Business Insider. “And Mahbod, our original community leader, is no exception.”

 3.    Disparaging the employer or coworkers 

Employees may use their personal social media accounts to complain about their work, or even outright disparage their manager or coworkers. But if they get caught, it can come back to bite them.

One Maplewood, New Jersey public works employee was fired after he complained on Facebook about having to pick up trash after a two-day outdoor concert, Maplewoodstock. Sam Falcetano complained about the public works department and the cleanup and then went into a “tirade against Obama, liberals, gay marriage, abortion and teachers who he claimed pushed a liberal agenda in classrooms, according to several commenters on the site,” reported NJ.com.

Some Facebook commenters defended Falcetano’s remarks and criticized the city for his firing. “”What a disgrace,” one commenter wrote, according to NJ.com. What ever happen (sic) to free speech and opionions (sic). he is 100% right.”

4. Disclosing sensitive, inappropriate information

Since nearly everyone carries around a camera on their smartphones these days, photographs are getting employees in more and more trouble.

A staff member of an assisted living home in Red Wing, Minnesota apparently got herself fired this year after taking a photo of an elderly resident on the toilet and posting it on Instagram, according to a local CBS affiliate. The photo was taken without the resident’s permission and showed bare skin just up to the upper hip area.

The facility’s handbook prohibited any photography of home residents. But the employee clearly took it a step further by posting a distasteful photo of a resident on her social media account without permission to do so.

5. Inciting or celebrating violence

How someone reacts to current events or news, especially if those reactions are seen as insensitive or celebrating violence and illegal activity, can lead to trouble. Managers at a Subway sandwich shop in Laurel, Mississippi recently fired a sandwich artist after she allegedly celebrated the shooting deaths of two Hattiesburg police officers on Facebook, according to a story in The Clarion-Ledger. The employee included such phrases as “GOT EM” and “no mercy” in her posts and could be seen wearing her Subway uniform in her profile.

“This kind of behavior is unacceptable and does not represent the values and ethics of our brand,” a Subway spokesperson said in an email to the newspaper.

All these situations might be good reasons for companies to think about creating a social media policy, if they don’t have one already. Employees should be responsible for reading, understanding and signing the policy to ensure that they know the rules, and to give the company more legal protection in case an employee abuses them.

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