What would you do?

This post is not meant to start a war over the vaccinate vs. not-vaccinate topic, but I do have a question for all you D-parents on what you would do in a certain situation.

Elise is not up-to-date on her vaccines. We've done a delayed schedule with her from the beginning, and we got behind around her second birthday due to illness and having to get both the flu shot an H1N1 shots. The ones we're missing are the MMR, Hib, and Hep A (which I am not all that worried about the last one).

I am planning on getting the MMR very soon because we're going on a trip up to Canada in the next few months, and the thought of Elise flying on an airplane, plus having to go through customs at the Vancouver airport with a bunch of international arrivals makes me nervous.

My dilemma is this; I have recently met a Mom who wants to get together on a play date. She has three kids, one who I know of for sure has never been vaccinated for anything. She is the one closest to Elise's age. She also has a 6 year old, who I assume comes into contact with a lot of other 6 year olds. Rounding out the list is a 6-month old, who I'm uncertain of if she's received any vaccinations.

It makes me nervous to expose Elise to any child who has not been vaccinated due to her having a comprimised immune system, and my gut is telling me to be careful. Am I being totally over-the-top cautious? Or do you think I should wait to have this play date until all Elise's vaccines are caught up? I should also talk to Elise's pedi (and will call her on Monday), but I'd love to hear what you would do.