Now if only jet boats on rivers used radar!

Kayaking is similar to motorcycling - you may legally have right of way, but in the real world, you're the one who's dead. So high-visibility colors (a big part of why so many kayaks are yellow) and use your eyes and especially your ears to avoid conflicts in the first place. Since I don't create any engine noise, I can hear a motorized boat coming long before they see me.

I'm fortunate that on a river, there is only a narrow channel that a motorized boat can take. I just head closer to shore when I hear one coming and then only need to worry about their wake (bonus rapid!).