Earlier quoted context omitted.
Where exactly is this 'implicit promise'? It's implied. Implication is in the eye of the reader/understander, not the stater/provider.
Other way round - When I'm talking to you, I can imply and you can infer.
I understand the grammar of it, but the question is: if one implies, and you don't infer the implication-- did the implication exist? It's basically the tree falling in the forest.
I've never read anything from Facebook that implies this. If they inferred it, they did so incorrectly.