Good luck with your case. Seems like you have a good chance of being successful (so long as the cop does not say your light was flashing).
And while I agree beacon is a strange choice of word, I don’t see it defined as a source of light visibile 360 degrees. Merriam-Webster has this definition
1 : a signal fire commonly on a hill, tower, or pole
2 a : a lighthouse or other signal for guidance b : a radio transmitter emitting signals for guidance of aircraft
3 : a source of light or inspiration