We were just talking about this yesterday in my family... I think you should take it as a sign of intimacy, that is to say that there is a familiarity and and comfort such that they are willing to share things about their personal life as though you know them on that level. Either that or they just aren't self aware enough to know that you don't have any idea who Emma and Jake are. The better approach is to say something like "I had to watch my son Jake for two hours" so that the listener has context, but of course that assumes the speaker is aware enough in their communication patterns to want to give the other party helpful cues.