There are probably discussion sites not dissimilar to this one where people who are into stolen credit cards and the like hang out to swap notes. It would only really take one person to post - hey check out this new thing - for a few to try it. I was a victim of a vaguely similar thing - having a squatter in my flat in Spain which went from something that didn't really happen to loads of them all of a sudden because someone put up a how to guide on the internet.