In two words: do it!
The idea of pressing seams always to one side is pretty old school. It comes from when seams were hand pieced; the double seam pressed to one side gave strength. Also, when hand quilting, it was easier to stitch in the ditch if the bulk of the seams was out of the way.
Moreover, it’s much easier to machine quilt if all of the seams are pressed open.
When I first began doing free motion quilting, I took a class from a teacher that recommended planning all of your quilting ahead of time so you would know which way to press your seams. (For machine quilting stitch-in-the-ditch, it was conventional wisdom to always quilt in the low side of the ditch.) My first thought was, what a pain!
I want the freedom to be able to quilt how I want when I want without being limited by piecing decisions. I also like how much flatter the quilt lies when all of the seams are pressed open. So yes, you have my permission to press ’em open as much as you want!
By the way, the quilt seams shown in this post are from my Bungle Jungle modern quilt I’m currently working on. You can read this week’s earlier post about making this quilt here.