Which is the point of this app, right? You don't want to let down your friend, so you're not going to cancel in the normal way; but in the case where the commit

Which is the point of this app, right? You don't want to let down your friend, so you're not going to cancel in the normal way; but in the case where the commitment no longer really suits either of you, it would be nice to take a night off, rather than both show up because you think it matters to the other person.