I didn't see anything like that in the user manual for my '07 Agility, but the mechanic where I bought mine was very passionate that ethanol "gums up the carburator!"
Still subsidy programs in Minnesota mean I also have very few options for "non-oxygenated" (keyword you should google in your area for non-ethanol gas).
I just rebuilt the carburator after close to 10,000 miles, and although a little dirty, did not seem excessively so for being 7 years old and using mostly ethanol gas.
That said, if I had a non-oxygenated gas pump closer than I do, I would absolutely use it every time.
Hope that helps.