Rear view mirror?

Has anyone ever used one of these cool bike helmet mirrors out on the water, maybe attached to the brim of a hat?  Some of the spots we kayak fish in Alaska have a lot of power boat traffic, and any time I hear a power boat engine behind me I have to turn around and check to make sure it isn't about to run me over.  Turning my head around changes my frame of reference for keeping my boat balanced, and one of these days I'm sure I'm going turn around to do a power boat check and catch a large wave at just the right time and go swimming (or maybe go swimming AND get run over by a power boat, wouldn't that be fun???).

http://www.amazon.com/Race-Icon-Bike-Helmet-Mirror/dp/B00SXHQP4C/ref=sr_1_3?ie=UTF8&qid=1459285283&sr=8-3&keywords=bike+helmet+mirror#Ask

I've used those mirrors biking, but not kayaking.  Most of those mirrors are designed to be mounted on a bike helmet, but some are designed to mount on the side of a pair of glasses.  See http://www.amazon.com/dp/B00XXQXNF2?psc=1 , for example.  The glasses-mounted mirrors would probably be better for kayaking.  On the other hand, if there are that many powerboats buzzing through the areas where you fish, perhaps you should be wearing a helmet!