metallo

That would be a clear violation of Alaska's contract of carriage (rule 7D) -- "Duplicate, impossible/illogical, fraudulent, fictitious or abusive bookings and/or reservations, or bookings and/or reservations made by Passengers with no intention of being used, are prohibited and may be subject to cancellation. A duplicate or impossible/illogical booking includes, but is not limited to, bookings for the same Passenger on flights traveling on or about the same date between one or more of the same or nearby origin and/or destination (such as SEALAX and SEAONT or SNASEA and ONTSEA), or bookings with Connections that depart before the arrival of the inbound flight. Fraudulent, fictitious or abusive bookings are defined as any bookings made without having been requested by or on behalf of the named Passenger. Additionally, creating bookings to hold or block seats for the purpose of obtaining lower fares, Mileage Plan award inventory, or upgrades that may not otherwise be available, or to gain access to airport facilities, or to circumvent any of Alaska's fare rules or policies, is prohibited without prior authorization from Alaska."

While it's very unlikely the OP would encounter any trouble with AS if using such a technique (as others have reported making a generous number of speculative bookings using wallet credits in the past), it seems fair to make sure the OP is aware that it's technically against the rules.

Good idea -- always safer to book backup flights on another airline.