I'm here at 182,000 miles to debunk the Priuschat myths

I'm with Ray.
I doubt very much you -could- "fill the carbon canister" with liquid fuel. You can certainly get -some- in there, but it still works, even when 3/4 full of liquid, just not quite as well. At any rate, it gets emptied first when you drive, so I don't think there would be any impact on emissions.
Prove me wrong with measurements.

 

I'll guess that the truth about overfilling the tank is somewhere in the middle: An occasional error is not going to damage the canister, but overfilling leads to release of unburned hydrocarbons. How much I cannot say, but I'll go with Toyota's recc and not embrace the practice. I'm happy to not worry about accidental spills, too.

I could understand a bit better Ray's point if the Prius had a 100 mile range, but as it it goes further on a tank than his F150 and the greater majority of other cars on the road.