If you are thinking of the likes of RQ-4 over North Korea then that is wrong also. The RQ-4 is still as vulnerable as the use of a U-2S over hostile territory. The North Koreans would have been launching SAMs by the dozen at any intruder deep in its airspace. Even downing UAVs would be valuable propagada for the North Koreans and something the US seeks to avoid. The recce flight are all periphery
The North Koreans are simply blowing hot air over the number of race-track patterns they observe along the mainland border and sea borders. The last over recce flights of North Korean airspace was when the SR-71 was in service.
I don't think that the US minds losing a few Predators.Those are designed to be expendible.It's the same everywhere-for eg India,Israel,Pakistan have all lost drones in enemy territories,but it's rarely been humiliating for them.
It's pretty unbelievable that the last overflights were using Blackbirds.The US needs very high resolution of places like Yongbyon & missile launch facilities-something that can't always been done using satellites.