Re: In order to ensure Libra isn't used for money laundering etc...
Facebook don't sell data, just the access to that data (think Cambridge Analytica). And if the third party spends half an hour working out the API so they manage to get a bit more than they should, well that's terrible of them (nudge, wink). It was expressly forbidden by the contract so it's not Facebook's fault for making a sieve-like API.