Hi Britt. I've tried to answer this at another location Error "Cannot do 3D operations on curved segments" which offers an option to solve this, but I cannot for the life of me find "official" documentation as to why it's not allowed either. Maybe someone will chime in between the 2 posts with more info.
Yeah that's pretty much how we've been getting around that problem too. We have instructed our technicians not to draw in true curves; and if they have to draw some in to make sure to generalize them before posting the edits.