But ethanol is not used as a fuel in road cars, only as an additive in
gasoline fuel. The Manitoba document you cite explicitly says you could
not practically use ethanol as a fuel in road-going cars.

Ethanol may be a high-octane additive, but it's a particularly poor
choice as a gasoline octane booster. Ethanol was a non-starter (ha ha)
before the government started hiding its real cost by taking money from
your left pocket so they could put it in your right, and then by
mandating the use of ethanol.

Ontario, Canada.

All the Shells in my province have that sticker, from what I've seen.

The Esso stations in my province all have stickers that say the gas "may
contain up to 10% ethanol". But then I checked the MSDS's for Esso's
unleaded gasoline. No ethanol at all, just MTBE (up to 15%).

Those pump stickers may be a legal labeling requirement rather than a
reflection of what's actually in the gas.

Shell's MSDS's do not even list the octane booster. They say only that
gasoline makes up ">90%" of the fuel mix. Shell is probably taking
advantage of the "proprietary" exemption from revealing its oxygenate in
the MSDS's.

I just did. The Manitoba government article is your typical
ethanol-loony propaganda bumpf. Manitoba farmers are reaping a
substantial financial harvest from the ethanol mandates, at the expense
of taxpayers across the country.

However, that article did contain this nugget:
"In order to produce Regular Unleaded gasoline with ethanol, a blender
must have access to an 84.5 octane (or "sub-octane") grade of petro-gas.
In some markets sub octane gasoline is not made available to blenders.
In these locations, Regular Unleaded (the lowest price grade gasoline
with the highest sales volume) does not contain ethanol. In markets
where sub octane gasoline is available, however, ethanol blended Regular
is usually less costly than petro-gas Regular."

I think the answer here may be that in my area they may be using sub-
octane to make Regular. Then they're relying on the heavy tax subsidies
that accompany ethanol to be able to offer heavily ethanolized Regular.

Grades above Regular may use better base stocks which do not require so
much ethanol to make them usable, but then the seller can't claim those
subsidies, so has to charge more.

And if our 91-octane uses MTBE instead of ethanol, there are no
subsidies at all.