sticks_us writes: By pairing an infrared sensor with the camera already on board, portable devices could receive data from transmitters placed, well, wherever. Beyond simply blasting out text and opening links like a glorified QR code, transmitters could disable certain features, such as the camera, to prevent recording at movie theaters and music venues. If completely shutting off the cam seems a bit heavy-handed, watermarks can also be applied to photos identifying businesses or copyrighted content... Link to Original Source
I've never been canoeing before, but I imagine there must be just a few
simple heuristics you have to remember...
Yes, don't fall out, and don't hit rocks.