Does this mean I should keep my phone on in class?

This is a classroom issue best addressed by your instructor. However, it is good cell phone etiquette to set your cell phone to vibrate to be respectful of others around you and avoid in class distractions

Safety and Prevention Tips

Fire Prevention Tip #5

Never tamper with life safety devices such as sprinklers, detectors, and fire extinguishers. It is a violation of state law to do so.