I don't doubt it. And I'm pretty sure they were meant to be seen, at least that was likely part of the mission, to collect intel on readiness, detection, reaction. Earlier ones also, but they got by and were only noticed in the data after scouring after the fact.
I'm more interested now in what the commercial ones were, who they belonged to, what they were doing, and especially if they were no longer being tracked by the owners, and if they were, why they didn't notice the national news, and if they did, why they didn't pick up a phone and tell someone, "hey, yeah, that's probably one of ours." And if they didn't know, why didn't the FAA know?