Yes. Operational Security. Friend to you, me, our lovers, special forces, politicians and hookers. Not generally for the same reasons but helpful to all nonetheless.
Thing is, facebook is the opposite of operational security. Facebook is the lovechild of the NSA, the DIA, and the internet. FB was the American testbed for facial recognition software and, if you are an honest person, has all your pertinent stats. Where you are from. Who you married and when. Your DOB. Your travel destinations for the past 10 years (if you were an early adopter). Your parents' names, DOB, anniversary, maiden names, and each of your siblings and where they live. It logs your phone number and can connect to your PayPal and bank account.
Which is why announcing on FB that you or your lover is deploying, regardless of where or when, is a bad freaking idea. You, yes you, without any help has just blown operational security to hell.
Consider it this way: your lover goes to Pstan by way of Astan and something happens like s/he/ze invades the wrong country. The brother of that cousin from that place where the invasion took place goes to Alma Mater Univ and sees by way of their housemate that your boo who is identified as being in Marine Recon Unit Y went to Astan a week ago and then took "an unexpected trip. lolz. but all is fine now. WRONG COUNTRY- whoopsies." This dude is pissed bc a drone just took out half his family at a wedding party and now guess what? He knows what you look like. What your whole family looks like. Where you live, where your family/your lover's family lives, and thanks to that helpful FB rant... what that soldier did last week. But more. This dude can get to YOU.
Is that too intellectual a point? How about this one- would you feel comfortable putting a full medical diagnosis for a communicable gynecological issue on FB? Or would you choose to inform close family and friends about that intensely personal journey by phone or in person...someplace your ex or boss or random gal from high school French who stalks you occasionally won't get all the gorey details?
There is a time and a place for sharing. For information that can result in you or your person coming to harm, loosing a job, or being tracked by casual life observers...watch out. Be discreet. And for theb love of Pete don't post on FB the day s/he/ze is deploying.