I noted a posting on the Kayak Ontario FB page (March 8), where a person rivetted a stamped aluminum plate to their kayak. I tried to save/copy the picture, but couldn’t.
We have the stickers in all our kayaks in the cockpit. We also added red and silver reflective tape to our sea kayaks for better visibility. I like the idea of laminating a copy of my driver’s license to carry on me. I may also laminate contact info and hang it inside on my hatch cover line - like a luggage tag.
Each boat has one on the thigh area of the inner cockpit, plus an “invisible” one inside one of the watertight compartments. I do have a photo of the serial number of each of them, too.
The US Coast Guard stickers are reflective to aid the SAR teams. Best to use a paint marker vs a waterproof marker to write a name and phone number and place sticker in a location that is easily seen by a boat crew or helicopter.