Besides some potential for corrosion of metals in the fuel system, Et-OH can also damage rubber fuel hoses.
See this pic of a post-mortem fuel filter:
http://forums.pelicanparts.com/off-topic-discussions/465200-slow-going-5.html
post #83
Not much crud (30,000 miles on the filter) but I have to wonder if the traces of black seen in the pic are rubber particles from the fuel hose. There is just a foot or two of hose before the filter, but who knows. I will replace all the fuel hose before next car camping season.