I was just saying that, should there be a delay in the mail the fish would survive at least a week or more. I wouldn't leave a betta in a bag longer than they need to be but I have kept imports in then for up to 3 days during acclimation (insanely slow).
Also if you lay the bag flat in the box it gives them a bit more room, and a little less depth so they can just lift their head to take a breath and their fins won't be smacked around as much. I've never had a betta arrive with shredded fins when shipped this way.
Who am I? Well I am a Junior Member of the International Betta Congress and a breeder of white HMPKs, red dragon HMPKs, black/red dragon HMPKs, metallic multi HMPKs, blue masked HMPKs, and now multi color HMs. Soon to add black HMs. I will be showing in New Breeder class in fall of 2012.