Whether actual fuel is exchanged - or numbers - audits are the only way to catch a cheater. A fraudulent biofuels producer could resell ordinary diesel with just a bit more effort than selling fake credits. A site visit to verify the production of actual biofuels is the method to detect either scheme, so the resolution would be no different.
> The interesting bit here is that is actually quite hard to figure out why what they did was illegal
This was outright fraud (creating and registering identifiers for fuel that never existed).
> The interesting bit here is that is actually quite hard to figure out why what they did was illegal
This was outright fraud (creating and registering identifiers for fuel that never existed).