Dearknees1
Their parents must be doing something right if they know how to behave away from home. That's what's always seems most important to me. Home is where I would expect children to be challenging. Our son was often described by others as well behaved and well mannered. We sometimes wondered who they were talking about!
Dearknees when I was told how polite and well-behaved my DC were when visiting other friends' houses I was pleased and surprised.
Far better that than a couple of children I knew who were, apparently, perfectly behaved, according to their parents, compared to other people's children but who broke toys, hit others and swore in other people's houses.
ps they did seem to grow up OK and one is a father now, I hope he's getting his comeuppance.