This quote from a mother of unvaccinated children in the article really got to me: “This is a private health matter, and not something people are entitled to know about unless I want to tell them.”

I suppose technically she is right, in regards to current HIPAA laws. But vaccination is, in fact, a matter of public health. Not vaccinating your children puts the rest of the public at risk, especially children who cannot be vaccinated because of other medical conditions or allergies, and infants who have yet to be vaccinated. I think parents who make the decision not to vaccinate are missing the forest for the trees. That being said, I'm not sure how or if I would bring it up.

Coincidentally, I was just thinking of this very topic yesterday as I was walking out of the pediatrician's office with a copy of my son's vacc sheet. I was going to suggest you use it (the topic, not the vacc sheet! Specifically, thoughts about vaccinated kids in school with unvaccinated kids) as a post topic, but thought against suggesting it b/c it sometimes the topic causes such a visceral raging response in parents on either side, especially in regards to autism. Even though your post is regarding playdates rather than school, I'm glad you did it and looking forward to hearing folks' comments.

For myself, I never thought to ask prior to a playdate.

There is a fantastic video on one of my favorite websites (ted.com) about the eradication of killer smallpox, and how finally, in 1980 (yes, it wasn't until 1980!) there was the last case of killer smallpox on the planet. The video is 26 minutes long, but around minute 4 is a list of the richest people on the planet throughout history that were killed by it. At minute 5 in the video, you get to see (warning: graphic and disturbing for parents) what smallpox looks like on a small child in the few days between exposure and death.

The video as a whole is actually thoroughly inspiring and full of hope, yet incredibly eye-opening in what it took to finally eradicate small pox:

http://www.ted.com/index.php/talks/larry_brilliant_wants_to_stop_pandemics.html

A related question--do you let your children play in homes where there are guns?

Both mine are vaccinated. But not because I'm afraid they might get the chicken pox and die. It's to protect the people they spend time with--the elderly, the tiny babies, the pregnant women, the relative with a compromised immune system.

That said, I have never asked my friends if they vax their kids. Mine are, so I'm not worried.

Actually its non vaccinated children who are ar risk from children who have recieved live vacines such as MMR due to live viral shedding after the jab.
If you child is immunsuppressed and cant have vaccinations you should keep them away from the recently vaccinated for MMR.