Who knows, but if they claim their refusal to say "Yes" to the question "Am I free to leave" actually means you were free to leave, I kind of doubt they'll get very far. And the safety exceptions won't be in effect after a few minutes of such obfuscatory questioning.

For that matter, I suspect most will realize that they aren't going to get anywhere with someone who's knowledgeable and disciplined enough to only say "Am I free to leave?", and will move on for easier prey. Spending "hours" in such a game isn't going to generate the arrest statistics they need, they'd only make that sort of investment if it was a really serious felony. (Unless of course their reward was an internal one of successful harassment ... and this sounds very tedious.)