Are D and E class starports Imperial territory as well? Isn't that stretching it a bit much for an E-class starport which is described as follows.
I am not sure if I were running a planet that I would want my only contact with the galaxy controlled by an outside power. Can local planets establish and run their own starports? And if not, where does it specifically say that in the rules?
Lastly, how is that going to be enforced in an asteroid belt, or a system with a large number of local spaceports for intra-system traffic?
The E-Ports (which almost disappeared in T5) might not, but the D ports certainly do count as extraterritorial.
Tho' there's no reason even an E-port can't be clearly delineated.
Also, keep in mind that the codes are the minimum services for that level. As long as one or more are missing from the next level, they might have everything else.
Looking at MegaTraveller (because it's to hand...
An E Port has a beacon and a place to land as the minimum.
A D port has minor repairs and unrefined fuel, as well as a broker.
A C port has major repairs (implying a crane-equipped hangar), a better broker (which implies multiple brokers).
A B port has a shipyard proper, a bank office, and even more and better brokers, as well as refined fuel ready for sale.
An A port has a shipyard equipped for jump-capable ship construction.
In theory, if the port has everything but a bank office, it's STILL a C-port... because you can't make your payments there, so it's not a B-port despite the Bilstein Yards.
So, an E-port in the middle of the desert may look like an A-port, but have no readily available fuel... at which point, it's an E-port.
As for enforcement... the Imperial agencies will only do business at the designated port.