Electrics Died When Starting Bike

This is a follow up to an problem I mentioned in another thread. Synopsis: when I pressed the starter button on my Bonneville Speedmaster the bike powered off. Turning ignition off and on again wouldn't produce any signs of life.

I now have a working bike back from dealer and they reckoned it was a loose battery connection, doh! That makes some kind of sense, I can imagine a not fully tight connection arcing with current surge from the starter motor resulting in a damaged contact area not electrically conductive enough to keep ECU happy (that's my theory, not dealers).

I'm not 100% convinced as when I asked the service desk to check with the technician they said it was the positive terminal, which is the one that is accessible and I had checked that by hand wiggling to check it wasn't obviously loose. Still, bike now works and the first thing I will try with any future problems like this is to remove battery, clean terminals and connectors, and tighten them up again good and proper.

I'm posting this mostly for posterity, and potentially for people to find via web searches if they have similar problems.