On the iPhone, grayscale mode (once enabled) is just a triple-click on the home button, so it's easy to turn off if you need color. You just need to remember to

On the iPhone, grayscale mode (once enabled) is just a triple-click on the home button, so it's easy to turn off if you need color. You just need to remember to turn it on after. Of course, if "scan for certain actions" is just feeding your phone addiction, then making it harder is entirely the point.