[Willie Green]

Reflective tape comes in different colors. Red reflective tape may have been too gaudy for them.

Yeah, but in my mind the terms "gray" and "reflective" seem mutually exclusive.

Perhaps they meant "silver" instead of "gray".

[Catspaw]

When I googled "reflective tape" it came up as silver/grey. My guess is "silver" might have them thinking it was a precious metal--and that'd be too gaudy, too.

And I just checked my sailing jacket--it's got white reflective tape on it. I've also seen reflective tape in yellow--that weird fire engine day-glo yellow.

[ArrogantBustard]

They mean "gray". The tape has microscopic retroreflective crystals embedded in it. It looks gray in diffuse lighting. Shine a bright white light on it (like an automobile headlamp) and it is as bright as any mirror, though does not form an image.