said by mackey:A properly constructed cased opening should be fine to run a cord through it.
Would you say it's against code to run a cable through a doorway (no door, just a door sized opening aka "cased opening")? How about a 18" square opening cased like a window would be?
Using a conduit, through a wall, is not a properly constructed cased opening. Protecting appliance cords or the use of conduit to construct a cased opening, are not likely listed applications for conduit, further making the whole concept not code-compliant.