We were discussing this last night at the Essex pub night, and it seems that my Hypermotard would be affected by this.
Thanks to the work by Steve in contacting the petrol companies to find out more about ethanol in the fuel (he's getting far too ahead of himself with only 7 posts!!) at least we know that using a fuel without ethanol in it will help to reduce this, if not stop it completely.
I've been lucky (!) enough to require filling the Hyper every day, so the chance of water ingress is much reduced, but I do store the bike over winter so draining the tank (read: going for a thrash until you run out of petrol
) sounds like a good plan before storage!
It will be interesting to see what, if anything, happens here in the UK with this.