A 'neck' could originally be a narrow stretch of wood, pasture or marsh, for example. This then evolved to refer to a settlement in a wooded country and then more generally to a neighbourhood.
A. Superstitions of the stage are numerous and many are particular to individual actors and actresses. That it is bad luck to whistle in a dressing room is a widely accepted belief. Another is that one actor should not wish another good luck before a performance but say instead 'I hope you break a leg.'