When the Israelis were in full control of Gaza, the Palestinians built tunnels underneath the Egypt-Gaza border to smuggle people and weapons. Now after Disengagement, the Palestinans have started building tunnels from Gaza into Israel proper.

IDF uncovers Gaza terror tunnel

Soldiers uncovered a Palestinian tunnel Saturday morning while working on a concrete, anti-sniper barrier near the Erez Checkpoint, north of the Gaza Strip...This was the first time since the unilateral withdrawal from Gaza in August 2005 that Palestinian terrorists have tried to burrow underneath the border fence surrounding the Strip.

The one thing I know is that the Israelis will be watching...and waiting.