I don't see the big deal in having a keycard droppable and having an underground market for it.
LSF/LN/LPI can engage at will anyone that isn't part of the government carrying around one of these. ( a form of contraband, perhaps one that would make the character KOS as soon as the Libs see that commodity) Granted, it doesnt' stop people from landing on a station and buying a million of these. Even a guard system would be a problem. However even with a bunch of these around, it would still limit people from accessing the gate.
Building it into the ID would actually be good to. Overall I think the keycard commodity would be interesting for interactions. (Perhaps even make it usable only once or twice and then have it decay away) But I do think the Jumpgate needs to be locked down in some form.
Edited to add: Idea: perhaps both? Build it into the IDs and have a 'hacked' card commodity that decays?
"The thirteen saloons that had lined the one street of Seney had not left a trace. The foundations of the Mansion House hotel stuck up above the ground. The stone was chipped and split by the fire. It was all that was left of the town of Seney. Even the surface had been burned off the ground.
Nick looked at the burned-over stretch of hillside, where he had expected to find the scattered houses of the town and then walked down the railroad track to the bridge over the river. The river was there."
