Add on the ability to wager up to the amount of marks you have plus 100 times the amount of VCs you have, and force VC->mark conversion.> You can change VCs into marks? I was under the impression that it was > only a one-way transfer. Pretty much. Converting Marks to VCs is voluntary; converting VCs to Marks only happens when needed to cover a Mark loss. pikhq's suggestion would effectively allow lossless VC transfers, by way of the intended recipient wagering on a statement whose truth value is already known, though it would only work when the intended recipient already has at least as many VCs as the amount to be transferred.
This was one of my concerns. It's easy to make a wager on the statement '1+1=2' here.
If modifying to allow VCs to be wagered (through VC->mark conversion) it may be worth 'taxing' it. e.g., 1 VC only gets you 80 Marks for use in wagering. Having said that, I prefer keeping it simple first and changes such as this can be proposed later.
Levi

