The Chabad Rabbis in Sderot think it may be worth a try. Here is a portion of an article that appeared recently in Israel's Maariv paper:
Despite the many tactics being used today, from targeted killings, developing anti-rocket weapons and fortifying homes—the inhabitants of Sderot are trying to find solutions from other directions in order to protect themselves from the Qassam rockets.
Now on the agenda: repairing mezuzahs. Religious officials in the city claim that examinations of mezuzahs there located many that were defective, and many of the defective ones were found in homes that had been hit. They said that in places where the Qassam rockets fell in the street and did not enter the yards of houses, kosher mezuzahs were found. Because of the security situation, ritual scribes from Lod have come to the city every Friday, checking the mezuzahs in homes and various public buildings in Sderot.
Until now, thirty percent of the mezuzahs that were checked were found to be defective or completely unfit. Seventy percent were found to be completely kosher. In the city’s schools, many defective mezuzahs were found, and the scribes reported this to the school’s administration. Similar examinations were carried out in the Sderot municipality, where the scribes were appalled to discover an unfit mezuzah at the entrance to the office of Sderot Mayor Eli Moyal and at the entrance to the auditorium.
Although in other places the scribes had asked people to buy mezuzahs and put them up, the scribes replaced the mezuzahs in the mayor’s office on their own initiative. “Moyal is responsible for the city and his office is the entrance to the city, so we did it,” said Rabbi Moshe Zeev Pizam, the director of Sderot’s Chabad House. “An unfit mezuzah does not do anything bad. It just doesn’t provide protection, and the inhabitants of Sderot need that very much.”
The deputy mayor of Sderot, Rabbi Oren Malka, said yesterday that the municipality intends to adopt the scribes’ recommendations and change the mezuzahs that were found to be unfit.
I think that the key thing to remember here is that it is important to have Kosher Mezuzahs on our doors just because the Torah says so and we are Jewish. If God protects us in the merit of doing this Mitzvah, it is a great fringe benefit.