Now I am in two minds whether to keep lending or not.
I was under the impression it was safe to lend because the trader borrowing the funds would automatically be liquidated by the system if there position fell below a certain %.
Obviously there is the potential threat of the exchange being hacked or going rouge but 30% APR return on Bitcoin is so tempting.
Don't take my word for how lending works, I don't know anything on how it works on exchanges, just that my own experience of it at BTCJam was really terrible :D