A. It depends on how much of a relationship you have with these scofflaws. If they're your friends, you'll need to confront them and explain what's obvious to you but clearly isn't to them: No matter how short the drive is, your child needs to be securely buckled into her car seat. To make it easy for them, strap the seat into their car before you leave, even if they aren't planning on an outing. You don't even have to tell them your kid ratted on them. Just go ahead and reinforce how important car-seat safety is to a neurotic nut like you (nudge nudge, wink wink) so that they get the point and also get to save face by having you be the crazy one.
If you aren't close with the parents, you could simply tell them that you'd rather not have your daughter driven anywhere while she's on a playdate. If it's too much of a burden for the housebound hosts, offer to have the kids play at your place as much as possible. That's been my solution since I learned the parents of my daughter's friend were neglecting to buckle anyone up (both parents are medical professionals, by the way). Although our children are friends, I didn't feel I knew the parents well enough to have either the bigger discussion or, more important, the trust that they would respect my wishes the next time.
You also have to wonder (at least I do) what other risky things are going on in this house. After all, when you let your child play at a friend's home, you're entrusting her safety to someone else for those two or three hours. Make sure you can trust the adults -- or make your house playdate central from now on.
Trisha Thompson is a contributing editor to PARENTING magazine and a former editor-in-chief of BabyTalk.