Employers argue that they are paying for your time (hourly workers), not the job done.  This is why you are not allowed to surf the net and play video games if you are caught up on all your work.  The US Supreme Court has weighed in on that one too.
If the employer (Apple, Amazon, Wal-Mart, whoever), wants to keep me around for whatever reason, they need to pay for that time.  Once they stop paying me, I should be free to go.  If my employer wants to do a bag check, it should be on their dime.
Now a quick 3-5 minute deal, I can probably stand.  15 minutes makes it to the timecard.
Yes, I am aware that the SCOTUS has ruled otherwise.  They also ruled Plessy vs. Ferguson (saying segregation in schools is okay) and were wrong then, too.  Given how they are being treated by Wall Street (how much does your wife make, Judge Thomas, or would you like to comment on the ridiculously overpriced weekend you took courtesy of the Koch Brothers?), it isn't surprising that no billionaire gets left behind.
No, your daughter isn't a princess because she gets paid for her bag check, or because she get paid at least minimum wage, or because she gets overtime if she works more than 40 hours in a week.  This should be the expectation of every hourly worker.
Its bad enough that wages are so freaking stagnant for workers while corporate profits soar, but to nickel and dime folks making $10/hour while making billions a quarter is just rampant greed.