Highporters and Lowdowners, Startowners and Locals

I don't have much of a Starport Authority IMTU. Fester maintains one, sure, but that's only what, forty worlds or so? So the definition of "extraterritoriality" is going to vary widely once you leave the Festrian main. But any world maintaining a decent port - or any agency on a world maintaining one - will want to reduce friction between the local population and outsiders. There will also be a desire to control the trade as it comes and goes.

The best way to do this is to maintain a highport, and insist on its use. All interstellar trade goes through the highport: everything and everyone coming in or out is kept under control. All A or B class ports will have a highport, so really, any safe trading world can be said to have one. Depending on a world's law level, it might actually be illegal for outworld vessels to land anywhere else onworld or to use a downport. (Who but smugglers and thieves would not prefer the facilities of a highport?) So for the most part, visitors to such worlds won't meet anyone but highporters: people associated directly with interstellar trade, with a vested interest in treating well with outsiders. Local laws may be relaxed; foreigners may be treated with extra care.

C ports, and worse, though, generally require the visitor to actually touch down in order to treat with the locals; C ports might have a shuttle, but that's all. Depending on law levels, there may or may not be firm lines drawn between the Startown and the rest of local society. And this is where your offworlder can get into trouble.

In any case, whenever a traveller leaves the relative safety of a startown, they can get in BIG trouble. They won't necessarily know local etiquette. They won't know the local dialects. They'll stick out like sore thumbs. This can happen even in Festrian space: in the frontier, there's no telling what trouble a traveller will meet.