I also wonder why anyone would do this. I have used E10 in riding lawn mowers, small engines, portable generators, etc for years. Some of them will sit for some time between uses. I have never had any issues. I do add PRI-G stabilizer to the gas that goes into these. This phase separation thing and other ideas, usually promoted by those that have some sort of ethanol phobia, I have never concerned myself with.... in almost 4 decades of ethanal blend gas use.
But to each his own. I never chide anyone for being cautious if their gut tells them to. I just never wasted any time worrying about such things.