In the past, the moon used to be sighted individually on a per city basis. The residents of that city would then inform the surrounding population to the extent of their ability to travel within a prescribed period of time. In those days, due to the absence of modern methods of communication, it was only logical for each region to sight the moon for itself. In modern times, that is no longer a necessity, especially for a country like Pakistan. Pakistan isn't an extremely large country geographically speaking, neither does it consist of multiple time zones. It makes no sense for them to celebrate Eid on different days.
Theoretically, the residents of a region are supposed to start Ramadan & observe Eid together as a community. This is applicable to nations as well. As I stated earlier, take the country's geographical size in to account. In Saudi Arabia for instance, a single committee is responsible for sighting the moon. Once it has been sighted, the entire nation must abide by their stance. What happens if that committee manages to make a mistake? Well, the populace is free of any blame on its part because another group has been delegated with the responsibility to look for the moon.
It's the same here when searching for "halal" food. The King has provided an assurance to the citizens that all the food to be legally made available in the Kingdom shall be "halal". If I was to eat something "haram" here unknowingly or if a restaurant had been secretly serving "haram" food, I would be exempt from all liabilities since the blame would reside on the head of the state alone. Why can't a similar solution for moon sighting be implemented in Pakistan? It's best to enforce the decision of the committee.
