I'm curious about a couple of things...and bringing it over to this forum since I'm looking for a sincere discussion and not just stories of people who say they were "wronged by the Man."

Question #1:  "Questions LEO's Ask"
* "Is this your car?" or "Who's car is this?"
* "Do you know how fast your were going?"
* "Do you have a firearm in the car?"
* "Where are you going?"
* "May I look in the trunk?"
* "Have you killed anybody tonight?"
* "Do you have any pictures of your mom?"
* "Would you like to buy some?"

...but I digress...

The first few questions.  I've already given them my license and registration, they can read who owns the car and all.  I understand that there are people who broke the law who aren't exactly MIT graduates and would answer such a question to their own detriment, but it also solves the crime for the LEO and without wasting precious man-hours for the city/state.

However, when asked those questions, I don't know of a law that would require me to answer them (with the exception of a CCW holder on the gun question in many states).

Regardless of guilt...

Would politely refusing to answer (or refusing to give permission) to such a question seem out of the ordinary for many LEO's.  Do most people just answer the questions?  And can an answer such as that be probable cause by itself?

Is there even a polite way to refuse such questions?

Question #2: "LEO Advice"
* The person has been pulled over, the citation or warning has been given. Then the LEO proceeds to give advice..or a speech or whatever.

If a person wants advice on laws, they are referred to (gulp) a lawyer.  If they were to cite advice from a LEO in court, it wouldn't go too far.

Surely there are different personalities at work as there are everywhere in life.  But beyond that, is there a reason for the street advice? Are there people who learn from such things as "Next time don't go 170mph through a school zone" and the like?

Well,  I really don't bother with the street advice, unless I truly believe they're clueless about the situation. Something that does happen fairly regularly, since just about any real world experience these days is from TV.  Does it work?  Maybe, although I have been getting pretty cynical over the years. As for the questions,  every bit of information you get, you verify.  Recovered a stolen car before it was even discovered to be stolen that way. Perp A said Perp B was his cousin, B said A was his brother-in-law, one claimed the car was his mom's, one claimed it was his girlfriends.  (I love those 2AM "Do you know where your car is?" phone calls) Yes, folks will trip thenselves up.  Do you have to answer?  No, but most will spin a story anyway.