Employees are idle during a lot of company time too. There's give and take on both sides.

No. Management will take and take and take during “crunch time” then immediately layoff large chunks of staff before they give anything back.

It’s happened scores of times. No company is as loyal to its labor as it expects labor to be to it.

And employees will take and take when not tightly supervised. How could you even begin to deny this?

That is a management failure.

And a management failure should not result in unpaid (slave) labor.

It's a contract violation by the worker. Even if no one's watching them, they promise to do labor for the money that they receive. And then when they don't do the work during the time that they're supposed to be working, they still get paid for it. That's theft against the employer.