The fuses I have experience with are indeed "blown" -- actual metal traces are physically opened with a large current -- and can't be intentionally reset. Ofte

The fuses I have experience with are indeed "blown" -- actual metal traces are physically opened with a large current -- and can't be intentionally reset. Often you blow fuses in multiples and take a vote, because the fuses can occasionally re-connect or have awkward leakage due to how the metal bits behaved during the over-current, and that's embarrassing for a fuse controlling a security feature.