Sorry if this has already been covered but my wife keeps asking me and I couldn't find an answer for her.

In several of the swap threads it is requested that the fabric used to make the blocks be unwashed. I understand that if some blocks were washed and some were unwashed it might lead to uneven shrinking in the finished quilt but won't using unwashed fabrics (especially reds next to whites) be a recipe for ending up with a red and pink quilt rather than a red and white one?

I tried to ask within the swap group but that thread doesn't get much action so I thought I'd ask here instead.

What is the advantage of not washing the fabrics before they are sewn into blocks?

Followup question: What is the best way to prevent the reds from turning adjoining white squares pink when the fabric in question is unwashed?

Any clarification you can provide is appreciated.