But that isn't how it works.

If you buy a ticket from PDX-CVG-EWR, that is what you paid for (Delta has no way to get you to EWR without using a hub).

If that price is $500, and PDX-CVG is $800, you have defrauded the airline of $300.

To me, it is as if I go into Best Buy and take a $800 stereo, give them $500 and walk out of the store.

Like I said, just because they won't prosecute you or sue you, it doesn't make it right.