I see... although I feel empathy for the author if he was scammed, it's important to make sure this isn't just an instance of laundering stolen a credit card through Upwork.
I think the entire plan would be built on attracting those who'd jump on the bandwagon without thinking critically about the situation much, creating as much resonance in the Upwork community as possible, and thus "bullying" Upwork into paying the money before they'd have a chance to properly investigate.
Given the attention the post has already received, I can't imagine how the "scammers" would be getting away with all this. But criminals aren't generally known to be very bright so I'd incline towards a risk assessment error on their part as, at this point, the situation seems be creating resonance not only among Upwork community, but probably among legal entities as well (which is quite ironic).