The best advise is to simply decline to answer any questions, and to keep anything that you would not want a police officer to see in plain view (including money). If they ask to search your car then you should withhold consent and this should stop the vast majority of issues.
There was an article in the Washington Post this week that talked about how much money local governments were making from these kinds of warrant-less seizures .
This may have worked 30 years ago, but no more. Refusing to answer questions is not only considered suspicious, but "failure to worship the ground that a cop walks on". They will search your vehicle without permission. If they find anything, they will just claim you gave them permission.
Most people just say "yes" to anything a cop wants. They have no idea how petty and vengeful many cops can get if you don't appease them.
People may say yes to what the cops request, but it is their own fault if something happens because they did as such.
The police have requested to search my car a number of times but have actually searched my car a grand total of never. They generally lead the conversation by asking if I have any drugs or weapons in the car then some time later ask to search my car. I decline, and he replies asking why and reminding me that I just told him that I do not have anything in my car. I tell him that I do not need a reason and that I have the right to decline. When he further presses the issue the only response he gets is that I do not consent to the search.
Good advice. It's not just all about protecting your cash from them. They can waste your time. They can be on a very annoying power trip. Very important to be respectful, but firm. US cops are nothing compared to cops in China, by the way.
There is very good youtube material on how to respond and act in situations with cops.
<--- this is probably what you are referring to (I am not affiliated with this channel, but I do think it does give a good explanation as to how to deal with police encounters that an average person can understand).
The police in China act differently because the people of China have much less rights then the people in the US.
