Cops and investigators of the USA should always check people’s identity cards and driver’s license cards at all times, doesn’t matter if you are on private property or public property.

The reason why to check the identity card and driver's license card of a individual. It would be evidence. Even if you didn't commit a crime or offense, the authorities still should have the right to check your identity-card or driver,s license. It should be a mandatory law, and if you don't comply, then you must be arrested. Remember, identity cards and driver's license belong to the public, not for you personally.