A cop can pull you over for having your interior lights on.
If the cop believes that your interior lights are impairing your visibility or is a safety hazard or if the interior light is being used for something that is distracting like looking at a document, then they could pull you over.
It's not illegal in most states to drive with your interior lights on, but a cop can stop under their own discretion if they deem the interior light as a safety issue.
An officer or cop has the discretion to pull you over if they believe that the interior lights are impacting the safe operation of your vehicle.
Also if you're pulled over at night, turning your interior lights on can also help ease the situation and show the cop that you have nothing to hide.
Cops can also legally sit with their lights off at night and hide to observe traffic and catch people violating traffic laws.
The cop can legally hide to observe any traffic violations and the cop doesn't need to announce their presence before they initiate the stop.
This is not considered entrapment, as entrapment involves the police inducing you to commit a crime that you wouldn't have otherwise.
Most times though the police may hide without lights and only light you up when they get behind you.
If the police car is not marked, you can call 911 and let them know where you're at and confirm that it's an actual police officer pulling you over.
Cops also don't have to have their headlights on at night and cops can also legally hide with their headlights off and they can pull you over for violating laws, even though they are doing the same thing.
As long as the cop or police have reasonable suspicion of some regulatory violation or traffic violation, like a blown headlight or taillights, turn signal lights etc being out, the cop or police can pull you over.
The initial stop is often considered a low level stop, but it also gives the cop, the opportunity to look for other more serious violations like open containers or expired registration.
The officer also has discretion in how they handle the traffic stop, and it often comes down to the officer's judgement at the moment.