If the ball band says wash and dry, I would. Did you wash and dry a test swatch? I've never had a problem with shrinkage in cotton knits, but who knows what different yarns will do. Don't dry it too long, if you put it in the dryer.
Cheating is an option. . . . Cheaters never win and winners never cheat, but smart knitters who want to retain an iota of sanity do, cheerfully. ~~Kory Stamper