If your classroom rules are the most important thing you do on the first day, you are teaching wrong… and this is true no matter the age of your students. OK… maybe an exception if you have potentially lethal stuff (chemicals, machines, etc.) in your teaching space.
Simple and effective technology solutions are not always welcomed. Many leaders want fancy and expensive solutions even if they are unused or used in a manner similar to the simple one.
Every instructor can be regarded with a "presumption of competence;" we assume you can to perform the duties. The best instructors recognize the "presumption of ignorance." They assume each class is filled with unique learners who make this group unlike any they have taught before.