"That launch deposited a payload into geosynchronous orbit but, given the stealth/deception hypothesis, there remains the possibility of other, undetected payloads"
There remains a "possibility" that dinosaurs aren't extinct and they're hiding somewhere. Just because civilian astronomers haven't found such payloads doesn't mean those payloads actually exist. And hypothetically even if those payloads do exist it doesn't mean other nations haven't tracked them.
Wikipedia isn't a reliable source for this stuff. Look at the basic physics involved.
Wikipedia isn't a reliable source for this stuff. Look at the basic physics involved.