How many users can change the settings of the Sengled Smart lights from their application?

My questions are keeping me up at night:

Can everyone who downloads the app control my lights?
Will my teenagers turn their rooms into a rainbow rave at 2 AM?
What if my mother-in-law accidentally turns off all the lights while trying to figure out the app?
Do I really have to give everyone access?

I spent hours setting up the perfect schedules – lights dimming gradually in the evening, soft warmth in the morning, and specific scenes for different times of day. The thought of six different people messing with these settings is making me break out in a cold sweat.
Please, someone tell me there are ways to control who gets access and what they can do. I love my family, but I also love my sanity and my carefully planned lighting scenes.