This is known in finance as arbitrage. Traders routinely exploit the fact that a good sold on one exchange might be priced differently on another, and they take advantage of that fact to (hopefully) score a profit. I added the "hopeful" bit, since you have to be fast enough to capitalize on the imbalance.
I would be curious, being of a fairly logical mindset, to know what the difference is. The publishers are setting up a system vulnerable to arbitrage, and expecting laws to protect them from the downside. How does that square with a free market economy, and how does protecting publishers promote any sort of public good?