These cards are obtained illegally. Buying them means you're supporting theft. It also means you will be liable in the (unlikely) case of prosecution.
Cheers.
Yes they are. The mere fact that they regularly go bad and people expect them to go bad proves this.
The fact that "sofia" replaces them quickly and without hesitation also shows they are getting them free (ie getting them with stolen credit card numbers).
Anyone that uses these is supporting credit card fraud, theft and encourages these hackers to do more and more to steal information from legitimate business, such as Target, Home Depot, etc who have been targets of data breaches.