I'm more interested in the chess example.
I don't consider "I've never lost a game of chess" when you haven't played a game of chess, to be a half truth at all. I believe it is the whole truth and nothing but the truth.
However, I still think it is misleading.
But I think it is the standard assumptive social norms that people habitually intuit that cause them to be misled. People mislead themselves by being presumptuous about the purpose of the speaker.
Basically: It is merely due to the fact that most people when they say "I have never lost a game of chess." do so in reference to games they have already played. It's simply weird and socially abnormal and quirky to say "I've never lost a game of X" where X is a game one has never actually played.
It's implicit bias in favor of social norms and against social quirks or abnormalities that causes this.
Nothing wrong with being socially abnormal (or rather, non-normal considering the negative connotation of 'abnormal')... provided that you are not being anti-social
It's possible to be pro-social but still socially abnormal. I do it all the time.
As long as the speaker isn't intentionally trying to mislead by saying "I've never lost a game of chess" when they haven't played, and as long as soon as they realize the listener is being misled by what they've said, they follow it up with "But of course that's because I've never played a game" (and such an odd and quirky/non-socially-normal statement can actually lead to laughter on behalf of the listener and hence be both socially odd and thankfully prosocial) then it is fine.
Lots of love from,
Mike the dude who probably has Aspergers Syndrome and is getting tested for it soon
P.S. I like being me.