It's 90% about
how you ask, and 10%
what you ask.
You just ask someone, "Where exactly are you catching all those crappie/trout/steelhead/etc?" and they're well within their rights to refuse to answer or outright lie.
You ask someone what to look for, what prime conditions are, or rough areas (say...not more specific than 1/4 of the water in question), and while they're still within their rights not to answer, doing so (or worse, steering you in the wrong direction) reeks of someone who's insecure (or...of course...blowing smoke about how much they catch).