Flying a long range unarmed stealth drone in lightly populated areas through the US would tell you a great deal about how observable the drone is to US radars. Flying dangerously through Air traffic controlled space also ensures that the military radars get pointed in your direction at some point or another.

For an unarmed small(ish) drone the risks of getting caught are likely minimal. Crash in an unpopulated area (plenty of those in the west coast), self-destruct at high altitude or simply acknowledge the spying incident and point to the SR-71/U-2 as precedent.