A U.S. appeals court has ruled that you can’t lose your job for cursing out your boss on social media, but don’t fire off that angry tweet or Facebook post just yet. There’s some fine print: The comment has to be a part of union-related activities, per BuzzFeed News. Note: strong language ahead. According to Courthouse News, the case goes back to 2011 when Hernan Perez of Pier Sixty and his fellow workers were told by a boss to “turn your head that way and stop chitchatting.” At the time, the workers were trying to unionize and the New York City event venue had a “no talk” rule in force to stop them from discussing it. Perez, a server who had been with Pier Sixty for 13 years, wasn’t happy about the incident and used his phone to vent on Facebook during a break. The Second Circuit quoted the entire post in its ruling: “Bob is such a NASTY MOTHER FUCKER don’t know how to talk to people!!!!!! Fuck his mother and his entire fucking family!!!! What a LOSER!!!! Vote YES for the UNION!!!!!!!” The workers voted to unionize two days later, and Perez removed the post when he realized it wasn’t private. He was fired when the company claimed the Facebook post violated its anti-harassment policy. The National Labor Relations Board ruled 2-1 that the firing violated labor laws. The three-judge panel of the Second Circuit upheld the decision last week, saying the Facebook post was “vulgar and inappropriate,” but “not so egregious as to exceed the NLRA’s protection.” The key? The subject matter was a “workplace concern,” in this case “management’s allegedly disrespectful treatment of employees, and the upcoming union election,” the judges wrote. The outburst “was not an idiosyncratic reaction to a manager’s request but part of a tense debate over managerial mistreatment in the period before the representation election.” Anyone thinking about using this ruling to justify their own social media outburst should beware of three other factors. First, the judges noted that one consideration was the fact that the use of profanity had been pretty much accepted at this particular workplace. The company “had not previously disciplined employees for widespread profanity in the workplace, including the words ‘fuck’ and ‘motherfucker,’ among other expletives and racial slurs.” Only five written warnings over profanity had been issued over six years, and no one had ever been terminated for it. “The [Administrative Law Judge] specifically credited employee testimony that Chef [Philip]DeMaiolo and [Robert] McSweeney cursed at employees on a daily basis including screaming phrases such as ‘What the fuck are you doing?,’ ‘Motherfucker’ and ‘Are you guys fucking stupid?’ Second, the profanity was on Facebook and not “not in the immediate presence of customers nor did it disrupt the catering event.” And third, the protection for cursing out your boss has other limits, and this case might be right at the very edge of them. “Perez’s conduct sits at the outer‐bounds of protected, union‐related comments,” the judges wrote. Maybe it’s best not to post that message after all.