I think they could guarantee nearly 100% if they could guarantee that they can get you to Landing Cover dive site. But, there is no way that they or any other operator can guarantee ahead of time that the wind, swells, current, etc will cooperate in advance. There are lots and lots of dive sites on Anacapa- both front side and back side and the Captain will have to make a "day of" decision on where to dive on the island, given the conditions. That is standard operating procedure in the Channel Islands for all dive ops.