I thought the ones Sarah used were surveyor’s marks.
That was what the Palin camp had said, perhaps because they feared the repercussions. However, even IF they were gun-sights, that is common place in the real world. Political campaigns frequency use them or speak about them, as in “in the crosshairs”. No one can seriously believe it is actually meant to encourage their supporters to go out and shoot their rivals or opponents. The phrase is also commonly used in sports, marketing, and any number of competitive arenas.
Anyway, the shooter was a liberal who was upset with her about some position or action she took on some issue.