What fun. Can you confiscate illegal equipment? As in, remove the "LED bulbs" or the "HID kit" right on the roadside, place them right behind a tire and order the driver to back up slowly?
Here is the funny part, the illegal equipment is actually evidence, evidence that a violation or crime took place. So, technically it is part of the job to preserve the evidence so that it can be presented in court... so if we take the bulbs and tag them into evidence then the car no longer meets the requirements that it have (head, stop, turn, etc) lighting equipment to be driven on the roadways, guess we need to tow it, right? Now this is perfectly acceptable and in all reality is the way it should be done, every time. However since most people consider vehicle light violations to be "petty", it almost never rises to this level. But it can, and it has, there is at least one guy who watched me uninstall the HID kits from his car while he sat in the back of my car waiting to go to jail... and then I tell the tow service not to release the vehicle until it has new headlights, so yes, it can and has happened, although not as often as it should. Now if it became a problem that my observation of the lights was not good enough in the court, and we started losing cases over not physically having the evidence to present to the court, then yes, we will take a lot more bulbs out of cars, and tow a lot more cars.
Think of it like this, you cant drive without plates/tags on your car and you cant drive without insurance on your car, if you get caught without either of these your car gets towed. Make sense?
And if you shoot and kill someone the police are going to take the gun and store it until time for your murder trial, the gun and the lights play the same role, they are evidence.