I think we live in an age of 'protect your a**e'. Yamaha cannot say that the Tenere is probably going to be OK running low octane fuel for fear that:

1. It goes wrong running that fuel for unspecified reason(s)
2. You thrash the guts out of it using 'bad' but available fuel, ruin the engine,
then sue them for saying it would be ok using that fuel.

I have heard that fuel people can 'cut' good fuel with low octane products to maximise profits, so the chances are we've all had a dose of low octane fuel in our bikes anyway.