"Officer safety" trumps everything it seems. It's the same logic behind immediately going for the taser at the first hint of non-compliance. Many cops would rarely kill or torture than risk pulling a muscle.
I use GoldMoney. No complaints at all. It's convenient, customer service is very responsive, and the storage fees are reasonable. This is the first I've heard of Bullionvault, so I don't know how the two compare to one another.
Rather than McDonald's, meet at the buyer's bank and watch him or her withdraw the cash before making the transaction. If you're really cautious, arrive at and leave the transaction location in such a way that the seller never sees your vehicle.
This article puts the security contractors at 5,100. WSJ LINK
I believe OSC-I, the military folks handling weapons sales to Iraq, will be approximately 200 personnel.