To keep this from getting abused it should require an empty core and maybe the same name as the entity it got undocked from (like the different entities and turrets are saved right now anyways).
Empty Core Required = means we are back to the issue of most people not using a failsafe on their reactors.
Same Name = would only cause issues for ships build by hand instead of spawned by blueprint or constructed by a shipyard.
I believe only triggering this when a either the raildocker, the rail its docked to, or both get destroyed, is enought to prevent most easy abuses, for anything further a simple check to see what blocks the entity is made out of could limit this to mostly only docked reactors.
Another way would be a kind of self destruct that can be triggered by logic, that actually kills the stupid core instantly, but that would requiere people to actually use it too.
Waitaminute ... so linked systems is worse than multiple collision detections occurring constantly? Howzat work now?
I dunno were you got the "worse" part, but linking very high amounts of blocks causes some issues too, so i believe Schine will only use it for low block count uses, logic and more complex modules like weapons and support systems.
Change Hull color by linking to a colored lights <- might explain it a bit.