Before y'all are too hard on your kids, consider this: Indirectness is the language of subservience. It means the person is in a lower place than the one they are addressing.
Think of Kings and their subjects: could the servant walk up and take a piece of the king's chocolate cake? Could the servant even *ask* for some of the cake? Nope! But...if the king was in a good mood the servant might be able to comment on how good the cake looked and, if the king thought of it, he might offer some of the cake to the servant....and no one stepped out of their role!
Kids don't think they have the "right" to ask, in many cases. Even when they do, they remember all the times they've been refused. They aren't sure of what rules apply and in most families, rules are applied haphazardly anyhow, so kids are never sure where they stand or what they can do. They're "lower". They know it. They do their best to get what they want/need while minimizing the risk of refusal.
Whatever happened to the days when a person could compliment without being accused of indirect manipulation? Is praise disappearing from the world?