A police officer can tell if you have current auto insurance or not.
However the law says that the police cannot just run your license plate to see if you have auto insurance or not and then pull you over for the no auto insurance.
As long as your tag is current on the vehicle and you have not done anything else to be pulled over then you can't be pulled over just for no auto insurance.
The police have to have something else to pull you over for before they can run your tag and check the database for auto insurance.
I have had to drive my vehicle with no insurance before because I could not afford the monthly payments for the insurance.
But my tag was always current and I was very careful to not get pulled over and mostly drove on back roads so as not to come into contact with police.