ATB Movement without Identity

A standard claim in the literature on coordination is that movement out of coordinate structures proceeds 'Across-the-board', a term originally due to Ross 1967 and worked out in some detail in Williams 1978. This is the basis for allowing exceptions to the Coordinate Structure Constraint (CSC) which disallows movement out of one conjunct if no movement takes place out of all of the other conjuncts. Despite some apparent counterexamples (Goldsmith 1985, Lakoff 1986), the validity of the CSC and ATB movement seems not to be in question. A related assumption, which supposedly follows from the ATB formalism, is that the element extracted from each conjunct must be 'the same'. This can be shown by the example in (1a) which seems to have only the interpretation of (1b) and not (1c).