Yeah, the tickets are given a value (significantly lower than a standard ticket) and that value is reported to the distributors and then cut back to the cinema; but it's a value that the customer doesn't have to pay.
So, e.g. at the cinema I worked at:
From internal point of view:
Adult ticket: £10. Customer is charged full £10, is reported as £10 revenue.
Child ticket: £6. Customer is charged full £6, is reported as £6 revenue.
Unlimited ticket: £3. Customer is charged £0, is reported as £3 revenue.
And then the cut the cinema gets is taken from the overall revenues. So if the distributor takes 2/3 of revenue, then for every Unlimited ticket booked, the customer pays £0, the distributor gets £2. The customer just pays their £17 monthly subscription, which goes straight into the cinema's pocket.