I got pulled over for not signaling. There was no traffic to affect.
The cop that pulled me over was in a parking lot so I wasn't affecting him. He saw my point and let me go. The only reason I knew this is because another cop had told me about the signaling law previously.
If you are in a left turn lane and turning and there are vehicles coming toward you, they gotta know you plan on turning in front of them. They don't know you aren't from out of town and don't know what lane to be in.
Laws are written ambiguously so that its easier to charge and convict.
Read a few tax laws and see how easy it is for them to stick it to you