The assumptions made by a listener as a result of intentionally limited data are not your responsibility in any way, indeed even if you were able to predict them with any reasonable level of accuracy, which you are not.
I have an essay pending on this exact topic.
http://www.glottopedia.org/index.php/Gricean_maxims
I find it unlikely that you really abide by this stated disregard of implicit assumptions - it would make communication impossible. The amount of information required to convey even basic facts is encyclopedic if you and your conversational partner don’t make use of assumptions about what the other already knows.
It turns out that if you abide by those linked rules, casual friendly discussions (things that are nonessential, for the most part) are pretty much ruled out. I find myself more often communicating with people who I have no explicit business or goal with, in social settings, and abiding by rules for cooperation on a team/task would make me a very boring person to speak to, indeed.
Basically communication is bidirectional, if the listener don't understand anything, it's probably their fault too.
Understanding is not a right or a gift, it's a process.
You can't force people to understand and no matter how you think about the listener, the listener have to do their part: listen.
I wouldn't say "probably". It might be. It might be the fault of the speaker. Or maybe both. Basically, my point was that it's not ONLY the listener's fault.
I.e., both sides have some level of expected interest/gain in successful communication and that makes each of them implicitly responsible (at least to themselves) for their part of gain from communication.
I fully agree. :-) My point was it does not fall only on the listener.
We all look forward to reaching a conclusion you didn't intend us to due to our assumptions.
By this logic, one can lie by remaining entirely silent. I don't buy it.
Yup. An example would be listening to someone reach the wrong conclusion, and by staying silent and not correcting them, implying that they were correct.
The listener's assumptions (or lack thereof), which happen after the speaker speaks, cannot retroactively cause the statement to be or not be a lie.
However, the original point still applies. He does not suffer from these issues, and directly communicated that he did. That is a lie.
At no point did he directly communicate anything about custody in his statement.
You are confusing implication with direct statements.
Whether you deceive by purposefully implying a falsehood or by purposefully denoting a falsehood it is still a lie.
Seriously, how far are you willing to go in your attempts to justify lying? You are basically saying "If I define my lie this way, it isn't a lie"
It's far easier and better for all involved if you simply tell the truth.