playdate precautions

I arranged a playdate for Daniel this weekend, but forgot to ask an important question. So it wasn't until we had been at the home for some time that I found out the parents and one of the kids had been sick with a stomach virus. Uh oh.
What questions do you ask before arrnaging a play date? Do you ask about pets? If snacks will be served? Do you bring your own snacks (enough for everybody)? Do you ask if the kids will play indoors or out and if the parents will apply sunscreen and bug guard? Don't be bashful, and as far as I'm concerned there are no dumb or offensive questions. These are your kids, after all!
-Misty