Originally Posted by mrcool1122

The grocery store analogy is inapt. One, who would ever call a grocery store to ask for a product to be held? Two, such a call does not a contract make. The grocery store is not accepting a promise from the nervous potential milk customer to buy the milk in exchange for removing it from the shelf. If anything, the grocery store is merely affording the customer a courtesy. The key difference being that the grocery store does not ask for a form of payment on the phone call, and would be free to sell the milk to someone else if there was only one carton of milk left in the store and another customer appeared and offered to buy it.

In the airline example, the contract is clear. The customer promises to pay, now, by clicking a "Pay Now" button and by tendering a payment method. The airline accepts the offer by removing inventory and putting it in a reservation.

"Illegal" is thrown around too loosely. It's not clear whether it refers to criminal activity or some other conduct that fouls the contractual relationship between the parties. Breach of contract is conduct that subjects the actor to liability for broken bilateral promises. Fraud in the formation of a contract may render a contract void and may create liability for damages. These are issues of contract law, not criminal law. And you don't have to actually receive tickets for it to be fraud; it is enough that the customer got some benefit. Here, that benefit is the holding of a reservation which the airline would otherwise not have granted the customer.