This seems interesting from a legal point of view as well: Is an app downloading, but never displaying, creative commons content infringing on copyright (by not showing correct attribution and violating the CC terms)? Besides copyright, could this be considered theft of service?
Is it? If you make a resource freely available to people online, and people access said resource, what's the legal ramification there? It would appear there is no malicious intent which would be necessary to make the case for abuse, and theft of service would be a stretch given that Wikimedia doesn't charge for their service.