Well, I think I have enough information to make my decision. I hereby vote that Nefario did not commit a scam by not honoring the fake GLBSE shares.
My reasoning, in brief:
1) There was no evidence presented that Nefario's original comment that he would convert the shares to Actual GLBSE was anything more than a possible offer.
2) Even then, no evidence was presented that Nefario mentioned what the conversion rate for these false shares would be. It would not be a safe assumption to say that they would be converted at their IPO value.
3) No consideration was provided. Nefario did not gain anything (other than maybe a very small amount of BTC in exchange fees) by offering to convert the fake shares to real shares. If it had actually happened, it would have only been out of the goodness of his heart.
4) Nefario has reasonably offered to buy back the shares at the IPO value. Trades above this (especially the 10 BTC ones) would have been absolutely ridiculous to any legitimate investor who actually did their research. Even if you go by Theymos's outrageous pricing, they've only gone up 600% in value from IPO. Thus, I consider those large trades to have been made out of stupidity and should not be valid for the purpose of this argument.
My decision is pretty firm at this point, but I will remain open to new ideas and opinions as they come in.
Let me present a totally different angle:
Nefario willfully destroyed the market value of undisputed bonds by the sudden close of Goats account. For example, instead of my TYGRR.BOND-A shares I now have a claim code of dubious value. It has been sufficiently explained how the claim code is a completely different, and insecure instrument to the shares originally offered, and Goat's obligations are at least unclear.
Even if Goat decides to honor the claim code the same way he promised in the original shares contract, there is no guaranteed buy back option in the contract. A large part of the original share value came from its tradeability on the free market on GLBSE, and Nefario destroyed that. Out of spite and to get leverage in a personal fight with Goat. Completely innocent GLBSE customers were taken hostage, and their property greatly reduced in value.
Indirectly Nefario also harmed GLBSE owners, as the angry customer backlash will harm GLBSE. He cannot hide behind GLBSE terms of operation, because:
1. Clearly he did it out of malice, and not to protect GLBSE.
2. He did not protect GLBSE, rather the reverse.
3. The stated terms are laughable and won't stand up in any western court.
I and many other GLBSE customers were harmed. GLBSE owners were harmed. Without cause and reason. Nefario is a scammer, or so stupid it does not make a difference.
-coinft.
PS: this is a sad story. I really liked GLBSE up until now, despite some rough corners and irregularities.