Is it just me, or does GPT4 respond better if questioned about content that might contain an error, without pointing out the error? Inevitably, if I accuse it of an error, it gets tied in logic loops much more quickly (flustered?)

Yep, it's called chain of verification (CoVe)

Co-Founder 

Contact: https://alice.chain.box

Are you saying the "nudging" the model vs. direct confrontation has a measured, predictable benefit?

Yep, it's called chain of verification (CoVe) https://paragraph.xyz/@metaend/chain-of-verification-ai-self-check