As I noted here in 2006, as well as in testimony before the U.S. Senate Foreign Relations Committee in September 2006 (which you may read here), it is naive to expect that UNIFIL, on steroids or otherwise, will move to disarm Hezbollah. Instead, the force has developed a "don't ask, don't tell" policy. The incident reported in the Haaretz article involves Hezbollah disrespecting that dictum. However, rather than confronting Hezbollah, UNIFIL responds to such incidents by restoring the rule, which is an arguably sensible policy so long as UNIFIL is not going to act as a strike force against Hezbollah. And, UNIFIL is unlikely to ever play that role, either to protect Lebanon's territory from Israel or to protect Israel from Hezbollah. What the force does best is act as a buffer force and a reporting agency. As such, it reduces the opportunity for an eruption of violence and its gives both sides an excuse not to fight.
Israel: UNIFIL is concealing information about Hezbollah - Haaretz - Israel News