True that. I've seen LAX reserves get used for SFO trips and such. Trick is that LAS reserves can only be realistically used to cover trips originating out of hubs (and only when those hubs are already sucking wind). However, LAS reserves are highly unlikely to get used to cover trips that come open outside of hubs since they'd have to double DH into position (e.g. someone calls in sick while on a SEA layover). Realistically, I think LAS reserves would get used more than GUM reserves but I can't imagine they'd be used any more than reserves located at hubs.