With several airlines (e.g. Southwest), it is easy to make a speculative reservation, cancel it later, and easily get full credit for a future flight.

Unless you have Elite 100K, Frontier's cancelation fees bite hard.

Recently, I tried something. A week before the trip, I booked a "maybe" (i.e. speculative) reservation using The Works for around $280. A couple days before the trip, I decided I actually wanted to go...and the lowest price was $140, so I canceled the original flight, requested a refund to my card, and rebooked for $140.

Does anyone see a problem doing this on a regular basis?