Do I have to stop at a DUI checkpoint?

Because you are required to have a driver's license in order to operate a vehicle on public roadways, you do have to show it to a police officer when it is requested. Aside from this fact, it is generally suggested that you comply with orders from a police officer. Refusing to do so only complicates matters, and can eventually lead to your arrest depending on the situation. Yes, there are instances in which you should say no or ask if you are required to do what the officer is telling you to, but for something as simple as showing identification, refusal is relatively pointless. Although there are certain actions that you are not required to take even when requested by a police officer, you'd have to prove to a court after the fact that this was the case. Less time and money is involved if you just avoid problems before they occur, rather than having to fix those problems later through court; "sticking it to the man" is not always as rewarding as you may think it will be.