SHOT Distracted me from jumping in earlier. Here are a few thoughts:
-Churches are targets for violence, we know this. Most people there are perceived as being perfect targets at peace and unarmed.
-most attacks against churches in recent times come from congregation members, former congregation members or member's families.
-Several churches have professional security, of course, they are larger ones, often with "celebrity" preachers.
-Many Churches have volunteer "security ministries" that provide security services (or a semblance thereof).
I do church specific security training from time to time, item # 2 is the hardest part for most serious non-professionals to deal with. Keep it in mind, when you form a security plan, especially if it involves firearms. The most likely person you will need to shoot is someone who looks like you. Think about Roeder. His is a home grown religious terrorist who shot a member of the congregation during services (his trial just started this week and he's in the news again). If there had been professional armed security on site, those guys would've needed to act without hesitation.
As FQ just said, training is the key for all of the scenarios.
(for the record, I prefer to do such training for the volunteer groups on the cheap or as a donation while I am in town doing another, profitable, course).
-RJP