Many puppies are very sick upon arrival.
You know how kids get sick more easily when they are “run down”? To a puppy with an immature immune system, the stress of shipping has the same effect. They're at risk for much more than a sniffle, though. Many pups shipped by "breeders", pet shops, and shelters develop potentially deadly diseases.
Shipping young puppies long distances during the most sensitive period of behavioral development can result in insecure, fearful dogs.
Often buyers get puppies that are not the breed/age/sex they “ordered”.
Inside Edition video on Internet Puppy Sales.
Sellers suddenly become impossible to get in contact with after the purchase of a sick, behaviorally unsound, or non-existent pup.
Scams abound- many people pay for puppies and never get them.