The thing is, the buyers in those cases were probably right. The fish they bought probably didn't look the same when they arrived. Remember when CWC and Dino got those beautiful black bettas? We got to see the seller's pictures, and then CWC's and Dino's pics, and the latter ones really looked pathetic.
Bettas blanch when they panic, and it can take some time for their color to return. These people are likely just expecting the
betta to come out of a day-long journey of shaking and loud noises and tumbling end-over-end none the worse for the wear. If they had waited a few days, their betta likely would have colored up nicely.