Well, if you are OK with getting paid in Ripple IOUs issued that can't be redeemed.
I have not said that I will let you redeem the BTC, I've even implied that you wouldn't be able to. It would be a clear and shut case if I told people that I would send them a bitcoin via ripple that they can redeem from me, versus sending them a Ripple BTC - which are not BTC.
It's like those 5 BTC coins with no value / private key on them that were selling recently, you know? They say 5 BTC, they are not 5 BTC, they don't have the private key of 5 BTC. When someone sells that for 0.04 each (or even free, in this case), crying in scammer accusations isn't going to help you - even if the seller didn't explicitly state that "they cannot be redeemed by BTCs". Example:
Casascius.com:
Each piece has its own Bitcoin address and a redeemable "private key" on the inside, underneath the hologram.
Now this would be an agreement. Or something similar, especially if it's signed.
An arbitrary token of an IOU with no terms attached is not. I would have broken an agreement if I used Ripple to send BTCs where I had redemption / repayment terms, and broke that.
Ripple is the same thing. It's OpenCoin Inc's fault for saying "send money" on their website, when Ripple is incapable of sending money other than XRP.