I would have thought so too but clearly European airlines do not think so as, despite them being legally required under the EU Reg too to call for volunteers, they usually seem very reluctant to do so and most will not actively advertise it, I guess that it because most of them want to do it before the passenger has gone airside and it is less practical to advertise at check-in when people trickle in (and where check-in desks may not be allocated to specific flights). KL seems to be more comfortable than most to deal with airside offloads and is therefore more likely to call for volunteers at the gate.