Campagnolo over-sized aluminum axle hubs (where you have the large non-drive side adjuster with flats on three sides and a counter sunk hex-head pinch polt to lock it instead of conventional cone + lock nuts or the single medium sized bolt for cartridge bearing Campy hubs) are reportedly built such that bearing preload does not change when you close the QR skewer and Campagnolo's adjustment instructions say nothing about there needing to be play which disappears.