muppetofthenorth,
The B-2 is a strategic platform. Under the terms of the various treaties covering strategic arms both the US and Russia openly reveal the platforms.
Heavy strategic bombers and their operating bases are subject to verification and inspections. The terms of the various treaties are public knowledge.
The following is the B-2 verification image taken by the Russians as part of the treaty. Note the photo calibration marker?
Link to other treaty verification images.
LETTERS SIGNED BY U.S. AND SOVIET REPRESENTATIVES
If the US or Russia developed a new heavy strategic nuclear capable bomber it would be subject to verification procedures. The type would become public knowledge as a result. Non strategic types such as the F-117 are not covered and as a result do not have to be disclosed.
TJ