There are some large churches in Texas that are possible terrorist targets. Any time you get 2000-20,000 people in one building, it poses a target to terrorists, just like a sports arena. Plus, it has the religious advantage of killing "infadels."
But, as Double Naught Spy said, there is a far greater risk of being shot by a crazed church member than by an international terrorist. There have been several church shootings over the years. I knew several of the people involved in the Wedgewood Baptist Church shooting back in 1999 (including friends with the Youth Minister). There have been several ministers shot over the years by people, many of whom were members of the church. And as the meth craze gets worse, more and more people will assume that churches are a great place for a handout, either voluntary or involuntary. And the latest fear among churches is the child abduction/sexual assault risk. Most churches now run a background check on all employees and volunteers who work with teenagers on down. Parents who do not have custody of their children have tried to pick children up from church, camps, and other church-related activities. And a church can be one of the most dangerous places for children to be preyed upon by sexual predators. I was on staff of a metropolitan church that had to get a restraining order on a guy who was following boys into the Men's Bathroom.
I see no reason why it would not be a good thing to have church members carry to church. Each individual should make sure that his or her worship is not hindered in any way and that carrying will not be a distraction, either for the one carrying or anyone else. As a pastor, I am quite glad that one of my members often carries to church! As the father of three young children, I want church to be a safe place for them to worship God.
Just my humble $.02 worth.