Dina (founder of Beyondapeanut.com which you should all check out) did a great job of giving a rational list of why parents of allergic kids worry about sending their child to a birthday party and ways to alleviate the stress for both sides. I think that these tips actually carry over to play dates as well.
How do you guys approach parents throwing the party your child is invited to? Do you all stay at the party with your child? Or do you go? If you do, what made you feel comfortable in doing so?