I wonder if sorting could be made feasible by mandating color-coding of different types of plastic? Like PET has to be clear, HDPE white, PP green, etc.? Marketers and package designers may not like it, but whatever. The tiny little recycling symbols seem pretty useless, unless you force consumers to hand-sort their recyclables according to them.
It gets worse: in King County, WA (Seattle metro area) where WM has most of the contracts we received leaflets from WM telling us to ignore the plastic recycling symbols entirely and to use only WM's "what we can / can't recycle" picture chart - which includes things I didn't think were recyclable (stained pizza boxes) and excludes things that I'd think were recyclable (plastic films).
...and the list varies within the county too: some cities' leaflets say not to put any pizza boxes in recycling (even completely clean ones). Aieeee.