All of them in this case did, with no families or major expenses to support, and not a weird scam or pyramid scheme, just standard contract development work where in two or three contractually secured months they'd make what they currently do in over a year. The reason is basically geographical, working for clients abroad is just ridiculously more profitable (think Venezuela).

The risk in this case is extremely low, I wasn't looking for referrals either (I'd offered to give it to them if there were any), just genuinely wanted my friends to earn more and work less.