problem is when you don't things get wonky as characters move around. If it is 1 bad guy and 1 good guy it works. But when you have 2 squads of stormtroopers and 6 pc's and you are trying to keep everyone relative position correct. That is where you start to have problems.
We haven't had a problem yet, although it does get a bit odd when people are flying around in vehicles and one of the players crashes and survives only to start shooting at some of the swoops which were flying around. This is something that I don't think the system handles well, and you have to be VERY abstract - Characters VS Vehicles.
Are PCs in one vehicle of multiple? As it is the many vs the many where you start to have trouble.
Multiple vehicles.
We haven't found this at all, and from my understanding, the math works. Its when people drop to character scale because of them being on foot, or are using character scale weapon ranges that the system gets wonky.
We tend to say that Close (Vehicle) is Short (Character), Short (Vehicle) is Long (Character) and Medium (Vehicle) is Extreme (Character). Obviously Starships are different again.