Have you disconnected the negative cable from the terminal post yet. I saw plenty of suggestions, but I didn't see if the battery had been disconnected yet.
The reason I ask, is that I left my Jeep ignition on, and thought I had killed the battery. No lights, no horn. . . .nothing. As I was disconnecting the negative terminal, to replace the battery, it sparked. Put the terminal back on the post. Turned the key, and motor started. It was as if I had completed a restart on a computer. I stopped by the dealer, and asked if there was a safeguard feature to prevent complete battery drainage. The said no. . . . but, I don't have high confidence in this specific dealership.
I do know that some bike manufacturers offer a "battery management" system; BMW for one. They told me that if the system sees that voltage has dropped to a certain level, it shuts everything down to prevent further drain, so you can start the bike.
If you haven't disconnected the battery yet. . . . give it a try. . . . while you're waiting for the fuse. Good luck, regardless.