Prius cabs are very common in Vancouver. We were downtown Friday, and noted on more than one occasion while driving there was Prius to our left and right, LOL. Safety in numbers? Herd instinct? Anyway: someone actually hailed us at one point, trying to catch a cab, LOL.
Around here they are painted either green or yellow; both in florescent hues with lights on the roof and vinyl graphics plastered everywhere else. So..... no, not a chance.
Because cabs make up a very large fraction of your Prius fleet, such confusion seems quite understandable. South of the border, the cab fraction is far lower, so we would be shocked.
I got hailed once while parked at a seniors residence, waiting for Grandma. I should have taken the old guy's money