It would be cool, but you could also place a piece of paper on the nightstand in each room with instructions for the same effect.
Technology doesn't have to be the answer for everything.
For static notes paper and pencil is the simplest and best technology. Smartphone app might come into picture if you want the notes to be dynamic or have personalized content.
"DON'T TOUCH THIS HANDLE - IT LEAKS!" -- it's sort of hard to explain exactly what handle I'm talking about in a bedside note, but trivial with virtual (or real) sticky notes.