My take is more tunnels are being built to kidnap-abduct Israelis and this can be a big psychological problem for the Israeli population. The drama and family in the news all the time. The speculation over what is being done to the victims by these evil evil bastards. What happens when Hamas gets to kidnap Israeli females?
Hamas has stated many times its objective of kidnapping Israelis to use as bargaining chips to get their imprisoned killers freed and to traumatize Israeli mothers and the nation
Notice that this escalated into the war we have after the 3 Israeli boys were kidnapped and killed
See the links in my post above yours. There were probably much larger terrorist attacks planned than just a few abductions.
The tunnels are also a perfect low tech delivery system for a WMD...