My theory is to go with the flow. If you find it difficult to do a totally straight stitch, or just are bored by it, do what you propose. I think it would add your own unique flair to the quilt. I'm thinking of doing the exact same thing for my next project which is a tee shirt quilt I have to have done very fast. I'm the finisher on a group project and have not gotten the blocks yet. I imagine this could be quite quick if you didn't quilt too close together.