Sorry, but everyone in the situation knew what was happening. There was no murder, in which the murdered person didn't know he was going to be murdered. This is therefore an invalid argument.
The investors knew that it may be a scam.
You kind of just contradicted yourself. First you say that everyone knew what was happening. Then you say the investors knew that it
may be a scam. Did the investors know it
was a scam?
Are you saying everyone who claimed it wasn't a Ponzi was lying and that everyone really did know that it was a Ponzi scheme all along? If so, the PPT operators who didn't say they knew it was a Ponzi were lying, just like Pirate. Right?
If someone comes up to you and says "I will steal your money if you give it to me, but I will fake very high interest rates to make it look as if you're making money." and you give him money, when he steals the money, did he really scam you? Scamming is lying/not fulfilling a contract. If, as you said, it was so blatantly obvious that it was a scam, then the PPT operators didn't scam anyone. They merely offered a service that they knew no more about than we did.
If it's your position that everyone knew it was a Ponzi scheme all along, then the PPT operators were knowingly participating in a Ponzi scheme. They're as deserving of scammer tags as Pirate.