Coming and sitting atop a hill or hilltop....A very uncanny resemblance of 1999 incident? Did someone learnt this from our western friend?
I don't think so. Our western neighbours did so in the delusion that they would get Kashmir. They thought that if they could perch themselves on hilltops, and cut off the roads connecting Kashmir to the rest of India, Indian Kashmiris would welcome a subsequent Pakistani invasion force with flowers and garlands. (The same delusion that made them do operation grandslam in '65). They had a real military objective in mind, although it was laughably out of their reach or capability. When India counterattacked with Bofors and Grads and mirage dropped LGBs, they had no idea what to do. They scurried back, or died.
In this case, PLA doesn't really have a military objective in mind. They are not so stupid as to believe that a few soldiers with banners would get them AP. They are doing this to appear tough, to send a message. But since the Indian side is not budging or relenting, and is returning ball for ball, they are not quite sure what to do either. They will go back in some time. They have done so before, and they shall do so again.
To keep it very short - China will not get Arunachal Pradesh through these risible antics.