Runeson's appeal to physical constraints seems to me not entirely foreign to cognitivist approaches. Perhaps that is another reason I find it so congenial, even if I am not convinced about its robustness.
In his discussion of the Ames Room, Runeson writes "Geometrically, the chances that an equivalent configuration would occur by random is therefore only 1 in a 100 million and that is for a very simple, barren case. For a room without the size restriction or with furniture and structured surfaces, the chances are many orders of magnitude smaller yet" (Runeson, 1988, p. 299) and "One must then ask, do prevailing physical and ecological constraints suffice to exclude the kind of room shapes that would be projectively equivalent with normal rooms? (ibid.)
At least some cognitivist accounts of amodal completion appeal to things like image statistics to account for the completion of the thing on the left and the non-completion of the thing on the right.