Basically Americans are banned from spending money that can be funneled back into cuban governemnt run p[laces or military controlled places. How they get there is irrelevant. Whether via a boar, a cruise ship, a plane from miama or one from toronto. Its the spending of the money by a US citizen on banned places.
all the resorts there are government owned, so technically, you cannot stay at a resort. there are no domestic flights to cuba, americans have to travel to canada, toronto to be exact, then travel to cuba and stay at a resport