The only problem with the BTA approach I think is the fact that a criminal could set up a rogue bus service that would collect people and then convince individuals that they either don't need a new spouse, or supply them with a dummy that they cannot distinguish from a real human being, and then kill a random woman on the bus.
In other words, this idea is not completely secure and tamper proof in its current form.
I started a similar thread here, which is based on the concept that for person A to receive currency C from person B, without any chance of keeping C, he would have to create a transaction T for an echanged currency C2 to person B, and only the id of T could then be used as a key (somehow) to validate the original payment from B to A.
But it's a chicken-and-egg type of problem, and solving that in a way that is close to the bitcoin "blockchain" way of thinking is beyond my feeble comprehension unfortunately. There are however some good ideas in the thread I linked to. Maybe they can be of use to you.
-Michael
You use certificates and keys to secure the server nodes. A rogue node could not transact with any of the P2P server nodes.