my guess of the sentence :
"I" want to dye or change the color of our blue badges so as to getting into the balcony, but since we are easy to be noticed so I gave up the idea.
if my guess is right (or not), then "to color a different shade" meaning to "dye or color it"?? why the word "shade" used here? what does "shade" have to do with color? why not just say "change the color of our blue badges" or just "color it"?
here is the sentence:
They wore little badges on red thread, marking them out as special. I wondered briefly if it was possible to colour our blue ones a different shade, but decided that being the only people with a wheelchair would probably make us a little conspicuous.
here is the context:
"they" are someone in the balcony, wearing red premier badges, while "we" are wearing blue badges on the stands watching races in the rain, freezing cold.
Best Answer
This definition (from NOAD) might throw some light on this:
This definition tells us that, usually, the word refers to a different but similar color; however, the word shade can be used a synonym for color.
As for why the author chose to use shade in this sentence, when the color change would be so drastic (from blue to red), no one can really say for sure. It looks to me like your interpretation is correct, that the author could have just as easily wrote:
and perhaps that would have been more clear (if that's indeed what the author meant), yet I wouldn't say there is anything wrong with the sentence as written.