Imma just jump in late...
What is so bad about valuing your own life and time?
Why should anyone be obligated to do mandatory favors for a boss and/or business without compensation?
If anything this sounds like the company and boss is all about "me me me." If people really need to be in 15 minutes before open then move the opening of the business back 15 minutes or offer all or some employees a few extra dollars to come in early.
The only time I would see the business being validated in this is if it is a really good job that is paying the employees so well this is a minor favor to ask but given people are quitting over this I doubt this is a doctors job where they are asking the doctor to please show up 15 minutes early before performing a C section.
This just sounds like a low end job trying to milk all it can from the workers.