Many cereal box liners are made from HDPE (#2 plastic) film. […] But plastic in film form (including bags) should not be added to your bin because it can jam up and damage recycling machinery. Instead, #2 plastic bags and other plastic film can be dropped off for recycling at one of thousands of retail locations.
Huh, wish I had known that sooner. We’ve started to see this marked on some brands of cereal (notably Chex), so it seems legit.