Yes, it's a violation of your privacy and a really awful thing to do, to boot.
Re: posting on FB. Gosh, I just don't think it's a good idea, most times. I do it sometimes. I like people knowing why I'm out of commission and posting "baby day" or something on FB makes it easy for everyone to know.
There are many times when I won't do it, though. For example, the only client I'm currently on call for is active in her local LLL (not my local LLL...she lives pretty far from me). Her local LLL leader and a few other members of that LLL (former clients of mine) are on my FB. If I post "baby day" on my FB, I'll effectively be telling her entire LLL that she's in labor, or that there's a very good chance she's in labor. If I say something today about "gotta get one more baby born and then I'm off call" and two days later I post "baby day" then yes, everyone on my FB who knows her will know she's in labor. I try pretty hard to keep my personal and business separate on FB, but it just doesn't seem to happen that way. First, it's a convenient way to keep up with former clients and their cute little babies (!!) and second, if a LLL leader or CBE or doula or LC friends me, it's a networking thing. I don't want to offend people who could potentially send me clients, ya know? It makes my FB have to be pretty anonymous. And it makes me cringe when DH posts things like a picture of me 8-9-10 OUT sleeping on the couch with a sick baby. But ya know, I think it's probably mostly good for my clients to see the human side of me, too.
SO, if I post something about a birth, I only do it knowing that no one who knows the mama is on my FB. I missed a birth recently (the only birth I've ever missed!) for a mama who lives so rurally that she doesn't have internet and who is new to the area she lives in (again, not my area, but not one that I've ever served before either). I posted about that on FB..."first time in four years as a midwife that a baby has beat me to a birth." I also posted a little more of the story in the comments (dad caught the baby, was thrilled, etc). I felt fairly comfortable with that.