Personally, I have not scammed anyone, because it is not that I am selling 1 BTC IOU on Ripple for 1 bitcoin. You may have your (bitstamp/etc) IOUs automatically exchanged for the IOUs I issued, but that is a flaw in the ripple system someone else is exploiting, not me.
Please note that you must exchange your bitcoins with an liquidity provider (Ripple does this automatically, when paths are calculated) in order to withdraw them from a gateway.
You have encouraged people to withdraw those fake bitcoins, aware that someone else would have lost his trustworthy IOUS from bitstamp, id est his real bitcoin, beacuse of you.
You cannot prove that you were not in agreement with people who actually stolen the money, or that you didn't steal.
I'm not in love with Ripple, i would have appreciated a discussion or a rescueless experiment; scamming is just scamming.