Disclaimer: Not a lawyer. But I am a business professor. This is not a cut an dried case by any means.
First, why was this policy put in place? Likely there was significant "shrinkage" in their inventories. Research shows that more loss comes from employees than customers. So, the policy likely came about because of the behavior of employees.
Second, no one is required to bring bags into work. If you bring a bag in knowing the policy, you have consented to being searched and have volunteered your time. If you don't want to be inconvenienced, lock your bag in the trunk.
Third, Apple was not making employees work during this time. The laws in this area are to prevent employers from getting employees to work without paying them. The only benefit that Apple got was to not have their products stolen.
I would wonder, were there 15 minutes during the day where these employees were not directly adding value to Apple? Do they want to give back money for the times when they were just standing around?
I very much believe that employees should have their rights protected, but I also believe that companies have the right to protect themselves from abusive employees. Since there was a clear remedy for this that would be easily implemented by an employee, I would have to side with Apple on this one.