Across many languages multiple sluicing obeys a clause-mate constraint. This can be understood on the empirically well-supported assumption that covert phrasal wh-movement is clause-bounded and subject to superiority. We provide independent evidence for syntactic structure at the ellipsis site and for locality constraints on movement operations within the ellipsis site. The fact that the distribution of multiple sluicing is substantially narrower than that of multiple wh-questions, on their single-pair as well as their pairlist reading, entails that there must be mechanisms for scoping in-situ wh-phrases that do not rely on covert phrasal wh-movement. We adopt the choice functional account for single-pair readings. For pair-list readings, we develop a novel functional analysis, argue for the functional basis of pair-list readings, and present a new perspective on pair-list readings of questions with quantifiers.