Here's a solution to the whole spending situation, which I've bodged on to my Contracts draft for know: "An asset generally CAN be transferred (syn. payed, given) by its owner to another entity by announcement, subject to modification by its backing document. A fixed asset is one defined as such by its backing document, and CANNOT be transferred; any other asset is liquid. To spend an asset is to pay it for the purpose of doing some other action or fulfilling an obligation; if the action would not be completed, the obligation would not be at least partially fulfilled, or more of the asset would be spent than is needed to perform the action/fulfill the obligation, then the attempt to spend fails."
-Aris
