Well if we follow your analogy, card counting should be allowed & casinos should just let it be - but in reality, you'd be kicked out faster than you can say "hit me".
Casinos are a different thing, and counting cards, at least in UK and US, is not illegal. Even more: Atlantic City casinos in the US state of New Jersey are forbidden from barring card counters as a result of a New Jersey Supreme Court decision. In 1979 Ken Uston, a Blackjack Hall of Fame inductee, filed a lawsuit against an Atlantic City casino, claiming that casinos did not have the right to ban skilled players. The New Jersey Supreme Court agreed, ruling that "the state's control of Atlantic City's casinos is so complete that only the New Jersey Casino Control Commission has the power to make rules to exclude skillful players."
When I was in my last year in high school, a classmate skipped classes to go to a casino. He had been there many times. This time, he won. And won big money, over 6000 U$S. In order to cash his check, the employee of the casino asked him for an ID. This had never happened before, and shouldn't have happened. He showed him, and the clerk said: you are 17, you can't be in a casino, please leave. But didn't want to return his check. My classmate called one of our professors to help him. Professor went and told the casino manager. You see: the fact that you have allowed a student, a minor, to gamble, is already a crime. We have photos and videos of a 17 year old teen gambling. We'll show them to the local TV station. In the end, owner agreed and paid the 6000U$S, which the professor decided would be wise to donate to charity. All the class agreed who to help, and we did an awesome trip to the mountains with books, two computers, a TV set, and more things for children that had nothing. And we also organized a trip for them to visit our city (60km away), and do a tour including visiting McDonalds, a first for most of them. Memorable senior year!
You think you're cheating the company, but you're only cheating yourself and other passengers, because in the end you're paying for it through higher fares. If airlines can't manage their revenues properly, where do you think they'll make up the shortfall? By jacking up the prices for everybody!
The company is cheating you when they don't allow you to fly a segment for which you have already paid! Why can't I cheat the company? I repeat: they were the ones to set the price. I accepted and paid. If it was too cheap, how can I be responsible?
Back to the example of the ASU-EZE-FCO-EZE-ASU route, that costed much less than the EZE-FCO-EZE route. Isn't it weird that 4 segments cost less than 2 segments? Sure it is. Am I the one who decided that? No. Am I the one who forced them to change prices so flying out of ASU has less taxes and less landing fees (I doubt this explains how it can be 700$ cheaper)? No. It is the airline who decided. This absurd pricing programs, that no one understand, and no one should understand, not even the employees of the airline.
Imagine you buy your milk every day in a small shop that charges you 1$, and then you find a large supermarket that sells exactly the same milk for 0,50$. Will you be to blame to buy it in a place where is cheaper? Will you be to blame if in Orbitz or in Expedia the tickets are cheaper, or you like the website more? No. In the current culture, the customer must always be right. Thats why when taken to trial, airlines (albeit having very powerful lawyers) tend to loose. I've quoted recent examples, one about no-show in Spain and another about "hidden cities" in Germany, where the airline and it's powerful legal team lost.
Unfortunately, it is not easy to sue an airline. It costs a lot of money and time and requires a lot of knowledge. Even, in the current case, we don't have all the information. Something I deeply hate is why airlines still use the telephone for changes or bookings. They warn you in advance: this conversation might be recorded. So I also warn them in advance: this conversation is being recorded. Because then, how can you remember all the details, how much are you going to pay, what is included, what not, etc? And we are speaking of big bucks now, sometimes many thousands U$S. How can we be sure the passenger who hates AA didn't heard correctly, or forgot to mention, or decided to lie and not to mention the employee told him about the no-show policy, or didn't? If taken to court, airline will say: we told him. He will say they didn't. Judge will ask: any tape of the conversation? Who has it? The airline, which, is inconvenient, could quote it is too old and has been erased.
Well you can't cheat the system by booking 3 nights in a hotel & stay only 1 to enjoy lower room rates...
I didn't want to cheat the system. I arrived two days late to the hotel. What's so wrong with that? I've paid for them. Why can't I use it? In my last awful experience, with a car rental company, a prebooked expensive car, they told me that it had no insurance to leave Spain and that in order to drive to Italy, I had to rent a new car, with a new booking number, and the previous one booking had no more effect, but I wasn't entitled to any refund. I got seriously angry. So I say: ok, give me the car anyway. Are you still going to rent the car and not go to Italy? I said: sure, I'll take the car, park it across the street, and bring you the keys back in 12 days. I've paid for it, so can't I do it? In the end, I didn't do it because they wanted a 1500EUR deposit (and my card is would be poor for the second car). At the end, the company did as a more or less good price in the second rental, and as we divided the bill in four, it wasn't so much!.
Actually I read the court document and the court didn't say that recovery of fare from a hidden city ticket user is illegal. However, the court did say that the airline needs to be more transparent on how much are they going to charge if they discover that the reservation is in fact a hidden city ticket.
Thanks for correcting me. I'm sure there is more of this story besides of what the news posted.