Your hypothetical example shows that you know nothing of raisin farming. The grapes are laid out on paper next to the grapevine, and don't move a centimeter until they are dried. Moving grapes that are mostly water to be dried at a second location is a waste of cargo capacity--you would be moving water just for it to be evaporated somewhere else.

But let's fix it by changing the grapes to ARM CPUs and the raisins to tablet computers. The chip fab decides to stiff the customer intentionally. You still didn't say who the known reneg recipient is. Perhaps an open-source tablet software project? If it is someone both parties are likely to support anyway, they simply reduce their donation by the reneg amount and blacklist each other.

With high-value supply-chain transactions, you probably want a lawyer-written contract in place and at least one face-to-face meeting. At the least, you know who the supplier is, and can go break his kneecaps with your lawyers. Or you pick an arbitrator and do 2-of-3.

The bonded 2-of-2 is pretty much just to solve the problem of non-recurring or rarely-recurring consumer-level transactions. If you want to buy weed online and can't trust a third party, you can put up bonds. If the assumptions of bonded 2-of-2 don't hold, you don't use it. One such assumption is that the 2 parties are anonymous and cannot trust anyone or effectively retaliate.

It could certainly be gamed. The FBI could take all of its Silk Road seizure coins and put up as many fake bonded 2-of-2s as possible. In the end, it would probably just end up funding a "legalize pot" PAC with a massive amount of coins, since it would still have to designate a credible reneg recipient, which must be clearly identifiable.