I used two shades of red to run this gradient from one end to another and then black and white. Blend modes were CIELAB under linear RGB and 32-bit floating point precision. Banding occurred when I down converted to 16-bit integer gamma RGB (i.e. sRGB). This small issue aside, I still think that I made the gradient appear like a solid red stripe, but this is something that I can't measure given the specification.
Can you measure perception by means other than asking?
Edit: removed a picture without clear distinction of colors. Changed the first one too.