Charted routes and interdiction

Some clarifications
Charted routes work through a combination of the natural curvature of local space and infrastructure in the systems they link. So new routes are unlikely to appear and the planetary governments along the routes have the ability to cut the power to the infrastructure and stop people travelling through. Interdicting fleets also have the ability to disrupt routes by shooting up the infrastructure (any damage is superficial; handwaving explanations on request, the real reason is that I can't be bothered writing yet another set of rules for replacing things you can't afford to fix).

Fleets actually in FTL mode are inaccessible both to fleets in normal space and to other ships using FTL.

A fleet in FTL mode using a charted route which is interdicted for any reason will stop at the last friendly system before the blockage.

Fleets arriving in system using a charted route have a plus 1 on their initiative roll (finally, some point to those routes between neighboring systems!)

Interdiction happens because an attack on a system has failed to result in a decisive outcome one way or the other. It follows that in order to interdict a system, the interdicting player must have had enough strength to mount an attack in the first place. A task force smaller than that is driven off by the planetary defences. A task force smaller than that which quibbles about this rule is blown to bits. By the S'''''wat, if necessary.