Not sure whether this is the best place for this kind of question, happy to move it if needed.
I'm designing a web application that will make use of a (non-free) third-party API. Paying a monthly subscription fee would give me access to a certain amount of API requests per month, after which I'd have to pay a flat fee per individual request above the threshold.
However, one thing that confuses me is that the company providing the service states in their terms and conditions that it's forbidden to cache user-requested data for longer than an hour, after which (and I'm quoting) I must delete my cache and refreshed the data via the API.
Is this limitation enforceable? What if the end-user is the one caching the data on their end? I'd have no control over this at all... If it makes any difference, the information provided by the API is not proprietary, the only service they offer is an easy-to-use API and some extra functionality on how to query the underlying information.