Same for the rest of what you describe: yes, a perfect system would be a lot of hassle, but making any effort at all is sure to yield benefits.

You don't need to change the billing model necessarily. The customers don't have to know that you are doing this kind of optimization.

Of course, the more you can expose incentives to your customers, the more efficient you can get.

But even if your containers arrive in arbitrary order and you have to make your decisions on where to place them 'online', ie before the next container arrives; as long as you have any choice left at all, you can try your hand at optimization techniques.

Also, consider that from the point of view of the people loading the ship, it's all insured. And if you didn't get the insurance then you understand the risk. Why would they care? They aren't the insurance company. What's their incentive?

The same effort is better invested into making sure you are not losing containers.

It's like saying 'we can optimise policing so that stabbings only happen to the right people'

Even “Even spread” would be a serious topic of debate - Even spread over what? Geographic area? Residency? Where people are likely to be at a given time? Those are three radically different answers in any commuter city.