It is very complicated, but ships like the Hegemon aren't restricted despite having battlecruiser-tier weaponry. If these so-called "battletransports" are used for trading, then there's no need to restrict them. They are already more than capable of defending themselves against pirate attacks, something that transports historically can't.
It adds another layer of bureaucracy that may take weeks or months for a response to go through, something no one likes having to face. To put, there's simply no need to restrict them, unless we get proof of them being used solely for combat purposes, which factions like Bristol (and Ageira) aren't known for.
