I think he proves a very big bug in the entire ripple system.

If anyone can make those imaginary BTC or any other currency in the ripple system, and he sends that fake currency to alot of persons..

User 1, Fake bitcoin owner try to buy something paying with bitcoins in ripple, starts a topic or something, and send the fake BTC first.
User 2, receives the fake BTC and send the item who was selling (LTC, ripples, USD,etc) then he realizes that he cant trade his BTC anywhere, because its fake and get scammed.