In our house, as with most households I assume, there are lots of rules that we decided on, which might not be agreed upon by other families. Our son is 9 at the moment.
For example, to prevent video game addiction, our son is not allowed to play when it's sunny outside. Without going into details as to how we came to this arbitrary rule, it's basically because we want to promote playing outside, but there is really very little to do Inside of our house so disallowing it on rainy days felt unfair.
Another rule we have is that treats should be eaten for dessert. We allow eating between meals only if it's a healthy snack, like fruits or vegetables. Ice cream, for example, is only to be eaten at the end of a meal.
Unlike in this question, our son never displayed a problem with that. He usually abides by our rules without complaining. But of course, many of his friends have different rules.
What we have noticed is progressively happening is that our son is going more and more at his friend's houses, especially in summer, and they are coming less and less here. They don't spent more time together overall, but this time is starting to be almost entirely spent at their places.
Of course, I can't decide what happens in another house, and my wife and I agree that trying to tie strings to our son will only result in him lying. We can't possibly check on him, and we can't control the other parents, so either he's allowed to eat sweets and play video games at their friend's places, or he's not allowed but will keep doing it behind our back.
The obvious reason why this is happening is that our son wants to do thèses things, therefore he tries to spent as much time as possible in households where this is allowed. That's totally logical from his perspective, he found a loophole and is using it. If I could temporarily move to a country with much lower taxes for 2 weeks when it's taxes season to save much money, I'd certainly do it too.
But another possibility is that the friends themselves find our house "boring", and are pressuring our son to play at theirs, where the fun is.
So my question is vague, mostly because we are constantly second-guessing ourselves with our first kid. What are we supposed to do?
Specifically, should we loosen our own rules at the expenses of what we believe is good for him? Is there a variation that wouldn't have negative conséquences that we could put in place (Ex: "You can do these things only when there are guests" would certainly increase the frequency of guests).
We, obviously, do not want to alienate his friends and isolate him, but changing our rules because another family did so seems particularly unfair, as if they were raising our children.
We are open to any and all suggestions, and will try to answer any question raised in the comments without compromising privacy.