Pretty sure there was no hard evidence posted anywhere for island data being corrupted by visitors pressing the minus button, only a handful of people who went "Someone left the game quietly and the next day I got an error". Probably correlation, in my opinion.
I do still want the backup option pretty badly, though. Being several hundreds of hours into the game, I can't imagine having the energy to start all over from that point where you have no tools and can do nothing at all...
More on topic, I usually don't find myself lacking anything in regards to materials and currencies. Sometimes I'm just in the mood to gather. I'm always happy to help the people who don't like doing that, too.
