Ten years ago, cameras and remote sensing were primitive compared to today. And with today's highways, Israel could easily cross Palestine in a very short time in a military emergency. Maintaining a troop presence is just to deny sovereignty. Is is not for security. And the presence of troops has nothing to do with rockets. Rockets were fired from Gaza when Israeli troops were all over Gaza, permanently stationed.
Clashes between IDF and protesters in Bethlehem and East Jerusalem (Reuters)
from the article: Israel could reconsider presence in Jordan Valley