Just because it can by beaten doesn’t mean making it harder isn’t useful. This person/team used a VPN. Masking your location is a big red flag for just dev work like this. These things could be exposed in UI.
People are so used to see artificial bureaucratic structures as more real than their real counterparts that they constantly invent such naive solutions. “Just make the gub'ment provide an official paper (with a stamp) that Joe Random Dude is a real developer, a father of two, not a fan of satanic metal music, and the project will be safe”.
The VPN is just part of the picture (sock puppet accounts complaining about speed of dev, no meaningful history of other contributions from the dev, no trusted "personal network" for the dev, etc) that in hindsight should have raised red flags.
If they constantly are on a VPN and not willing to disclose a real location or IP then I fail to see why they should be trusted when they don’t provide anything trustworthy themselves.