Anonymous participant 268 never heard of that unwritten rule, we’ve been to several countries and never had any issues. They may ask a question or 2, but nothing wrong with that. When they see me it’s all okay.
Maybe it’s more when kids are maybe younger, but mine are 15 & 12.
My 12 yo even flew back home to visit family and friends for a month, also no issues.
I think it’s also how kids are raised and the kids themselves. I raise my kids to be independent and confident in what they do and they need that independency. So they know what to say or do when questions are asked in these situations
Anonymous participant 268 because is works faster and my kids are perfectly capable of going through customs by themselves. We always do like this and it’s not that I’m way on the other side, just the next lane