I used to not use my blinker, then I realized I was being dumb and/or opening myself up to some liability. So for the past few years, it's just become habit. Lately, when I'm extra petulant and pass someone who was being a complete a-hole, I'll not use my blinker on purpose (I know, I know). My point is, that when I do this, I *know* I'm not using my blinker and immediately feel like I'm doing something unnatural like when I drive 5 yds to move my car, without putting my seatbelt on. As soon as the car is moving and I don't have my belt on, my body just goes "wait what, where's the belt?" That's how I feel now when I don't use my blinker. So I bet you used your blinker, and perhaps he knows that you can't prove that you did and he's just revenue'ing.