I really can't see the need for premature bans. Has there been a significant amount of accidents involving the use of delivery drones? I don't think so, so why potentially limit your competitiveness? :(
Also, it's fair to say that the AF doesn't really care about the potential for ground casualties in the event of a mechanical failure.
Let's look at it this way; how many US drones have been captured by enemy forces? Crashing is one thing; falling into the hands of an opponent who can study the device is a mission aspect that the AF and other agencies do care about. More than a handful?
[0] http://www.theguardian.com/world/2012/jun/12/us-military-min...
I find many of the other comments nearby are carping about details but not really addressing the point, which is that these things can and will crash, which is why they will be regulated somehow.