Taking advantage of the momentum following the dramatic destruction of the fence separating Egypt from the Gaza Strip, Hamas threatened late last week to pull a similar stunt at the Erez Crossing. But while within the IDF the proposed responses seemed vague or insufficient, some argued that the events at Rafah would actually reduce Hamas's ability to organize a mass demonstration. Last week, senior Hamas official Ahmed Youssef warned that "the next time there is a crisis in the Gaza Strip, Israel will have to face half a million Palestinians who will march toward Erez. This is not an imaginary scenario, and many Palestinians would be prepared to sacrifice their lives." Yoram Schweitzer, a senior research fellow at the Jaffee Center for Strategic Studies and the director of their Program on Terrorism and Low Intensity Conflict, said Sunday that the "incidents in Egypt may have given an outlet for the pressure" that had been building up in the Gaza Strip as a result of the shortages there. It could thus be more difficult for Hamas to organize a march on the scale described by Youssef - 500,000 people would mean that approximately one out of every three Gazans would participate in the protest. "People would either have to be extremely angry and 'choked' - or very, very loyal to Hamas," in order to respond in such numbers to a call to participate in a mass march on Erez, Schweitzer said. "Before, they could depend on public anger and frustration as a mobilizing force, rather than simply the organizational ability of Hamas." Since the Hamas takeover in June of last year, the largest march held thus far in the Gaza Strip was one sponsored by the anti-Hamas opposition in September, in which an estimated 10,000 people turned out to pray publicly in the streets rather than in Hamas-controlled mosques. In comparison, observers have estimated that somewhere between 500,000 and 700,000 Gazans have passed through the remains of the Rafah border fence into the Sinai over the past five days. The IDF has said in the past that it would respond to such provocations by utilizing nonlethal crowd control methods, and maintain its usual rules of engagement, in which troops would use live fire only if physically threatened. Even in such situations, the initial response would be to fire into the air, then at would-be assailants' legs - and finally to shoot to kill if the attack did not cease. Schweitzer said that if such a protest ended with Palestinian casualties, it would have serious implications for Israel in the international stage, increasing the media victory for Hamas. "They know that the use of civilian protest to pass along a political message can be more effective than shooting bullets," he said, emphasizing that "Hamas knows how to use psychological and media warfare to its advantage." He suggested that security forces attempt to place physical - and intelligence - obstacles in the protesters' path, as well as utilizing nonlethal technology. Among the methods already in use by the IDF is "the Scream" - a machine that releases sound pulses that cause nausea, disorientation and dizziness. US forces in Iraq have found that their Active Denial System (ADS) - known as the "pain ray" - is also quite effective in crowd control. The ADS - which, unlike the Scream, cannot be blocked by plugging one's ears - is a strong millimeter-wave transmitter that excites water molecules in the skin to around 55 degrees Celsius, thereby causing protesters to experience a burning sensation, without actually burning them. It is believed, however, that prolonged exposure or malfunctions leading to increased strength of microwaves could be fatal to protesters.