Ok it sounds like the South Koreans are stumbling (probably due to the much increased volume) and it looks like the Japanese sellers are on the rise since there are so many more new sellers from Japan but their prices are a bit higher.
There were posts on this a year ago, but here's more from Washington Post todsy.
In dozens of U.S. cities, the next time you call 911, a drone might show up before an officer does.
The technology behind that — “Drone as First Responder,” or DFR...
Why not get some cardboard or plywood or something similar and test it out on the ground and let us all know as well as which drone you are asking about?