There was also a small point of having a warning flash on your info panel telling you your flying un-insured, that could populate each time you change your frameshift state, when you enter or leave super cruise or hyperjump.
About thing suggested in another thread was an insurance or rebuy lock in the systems panel / functions window (same place as orbital lines off are) this would need default on and would prevent you unobtrusively from spending above your rebut cost and if you take it off, well, there is one less excuse (not that it will stop people, some will turn it off and then come to tell us here on the forum about it when mr Murphy clobbers them)