Some crypto currencies , especially some stable coins, ( plus Facebook's Libra ) claimed that "backed by non-digital assets"

Let's go back to 1963. 

Salad Oil Scandal , also known as Soybean Scandal.

A trading company brought 1.8 billions of soybean oil to the U.S ports with many ships.

U.S Customs inspectors checked ships and confirmed that ships were full loaded with salad oil ( soybean oil )

this customs checked allowed trading company ( Allied vegetable crude oil ) obtain millions of loans from banks.

in fact, ships were loaded water and few feet oil floating over water. In numbers, actually 110 million pounds of soybean oil were in ships rather than declared and "checked" 1.8 billion pounds of soybean oil.

Bank of America , American Express and some other institutions were hit badly about this scandal. Amex shares down %50 percent and total loss in 1963 was 150 million USD which is roughly equal to 1.5 billion USD in today 2019 

Negative effect was limited because USD was particularly backed by gold in 1963. Gold standard was totally removed 8 years later, in 1971. ( started in 1933 but gold price against USD was fixed until 1971 )

Now all banking system based on fictitious money in all countries. 

We got lesson from past scandal that auditing or checking by officials do not guarantee %100 accuracy of information.

another example is Chevron Scandal which later leads to born of Sarbanes - Oxley Act. 

simple questions :

- how some stable coins backed properly %100 by assets ? 

- bigger question is for Libra. how it will be audited "accurately"

I do not offend to Libra or any other stable coins. Possibly everything goes well.

But is it a potential risk for creating domino effect on entire financial system ?

just crazy questions on my mind.