the creator of ethereum said the following:

Replying to @VitalikButerin @IlaMilkEs and 4 others
Particularly, I recall the whitepaper says it doesn't offer oil, it offers bolivars based on the oil price. On top of risk of total default, this gives them opportunity to do a partial default by manipulating the official bolivar rate, which they have a history of doing.

https://twitter.com/VitalikButerin/status/966308397103570944

- VitalikButerin