I run eth-free gas in pretty much everything (cars, sleds, small engines) other than my truck (diesel); I've been aware for a long time that you get some eth if there's blended gas dispensed from the same hose, but I've never worried about it. Even if it's a full gallon, it typically ends up being a very small amount of ethanol. Most blended gas is "E10," it has 10% ethanol by volume. So if you drive up and fill your sled and there's a gallon of blended gas in the lines before you get the good stuff, you're getting 1/10 gal. of ethanol (less than a pint). You'd end up running just over 1% ethanol, assuming you typically fill around 8 gallons.
It is a big deal if you're filling a typical can for your lawn mower or whatever, but I say it'd only be enough to worry about on a sled that gets topped off a lot. If you're really worried about it, either find a pump with separate hoses (half the stations I fill from do), or run in ethanol mode. Or just don't worry about it.