Not impossible....There could be fake bitcoins if you had 51% of the network hash power. Although Second Life only says 'Fraudulent transactions' and of course never gives specifics as to how.....Thus the risk api. It limits you by how old your account is, and how much 'exhangeing' you do. Im not well versed on the specifics.....
From
http://therocktrading.com/topics/96"In reply to Re: General Halt updates
Dear Friends,
as you may know, for the past few months we had issues with Linden Lab.
It all started the moment we decided to trade bitcoins vs lindens.
Here is the story of what happened or, at least, what we believed happened because we never got too many details from Linden Lab.
After a short time since our Bitcoin exchange opened, a major player started to move a lot of lindens/bitcoins. A couple of weeks later, all our SL avatars and few of our regular Customers were frozen and funds seized for an ongoing investigation….
Please, it is important for you to know that, before we were stopped by Linden, we alerted Linden about the Suspect because of his unusual volume. Also, it is important to know that, before the stop, the Suspect had limits with our exchange.
It took few days for Lindens to solve the issue and return all our funds (and our customers too). Please note that the “suspect” was released as well without consequences.
At that point, because the suspect was investigated and released, we assumed he/she was ok and let him freely trade on our exchange raising his limits as well….. Also, the suspect, provided payment info with Linden on top of his docs.
Finally Linden gave us RISK API after many months of our request….
At that point, out of the blue, one morning our exchange account dropped from a little less of 2 million down to more than 10 million!!! Linden Lab charged us for almost 12 million but never suspended our Avatars…..
After few days it come out that they seized the funds because of illegal transactions made by an avatar before RISK API. They never released the name but, the only Avatar that moved so much was the Suspect….
Of course, we emphasized the fact that they allowed him to continue his fraud after the first investigation and it was not our fault to assume he/she was not acting honestly…. But, with Linden, you do not really have many chances to argue…
We had 3 choices:
1) Fight them back legally
2) Close the business
3) Find an agreement
We choose the 3rd option because the first one was too complex being overseas and we did not like the second (which was the most logical!!!).
In the end, we agreed with Linden to pay on a monthly basis 50% profits of our holding Company The Digital Rock.
What does it mean?
It means that our investors and shareholders are not affected by this accident because we will fully absorb it from our income.
Now, I challenge anyone to find in the past or even in the present any other company or exchange to accept such a deal in the interest of its investors…..
Thank you again"
I dont want to sound like an expert about Lindens, because frankly I am not. This is just some of what I uncovered after attempting to buy Lindens with Bitcoin.