Bandit, striker is just addressing the technical side of things where you're addressing the visual side.
You're both correct, but just in different meanings... The light will look purple from certain distances and angles because of how the light is bending due to the projector. That's why if they're far in your rearview, their car is jumping up and down bouncing "purple" beams at you, but when they're right on your ass, it's white...