While I think a ad source such as Craigslist is OK, it depends on what was for sale.
What was the price, where were the puppies at, why are they being sold? Are these puppies by the breeder, are they available for inspection at the home/kennel?There are so many scams in every type of dog breed and buyer be aware is not common sense for many people.
Do a ad search and see how many "For Sale" websites pop up for all types of animals.
Everyone can help to educate the public about scams. What to look out for and what are problems and concerns with low-priced Bullies.