Personally, I don't think that it increases any danger to kids, I use my real name and post pictures of my adorable kids all the time, but I respect those who feel differently.
It does? I have a blog, a well-used Facebook profile, an active twitter account, and I comment on Reddit and HN all the time—but the last picture of me that exists on the public internet is from 2005. All the photos I actually want to share with my family are in a shared folder in my Dropbox account.
I guess I have a strong mental separation of my public and private lives; I would never talk about my family on my blog, nor would I talk about my job on Facebook.
Part of what the original article was talking about is that having a "real names only" policy makes it harder to keep that strong separation of public and private lives.
Google+ lets you approve all tags.
If I had a kid that I was bringing along with me occasionally, there could easily be photos of them on there too. A real danger? Probably not. But what if I had an ex with a restraining order against them, and they didn't know where I, or my kids were living? That could be a potential issue if they were name searchable, geotagged, etc.
I guess the real point is that I can't imagine all of the situations, because they probably don't apply to me right now. You can find my address, phone number, email, employment history, favorite coffee shop, online easily. Yet, I'm ok with that. Not everyone would be, and that's understandable.