I found the article very good. Some very good, simple security concepts were outlined. In the region I live in there have been multiple "events" that have occured over the last several years. Many that made the local news involved breaking and entering and theft. Several have involved assaults.
I think that many times if the churches were able to install some strategically placed exterior cameras with a good midrange recording device and some carefully placed exterior signage (not intrusive, but clear and concise in several languages), the deterrent value may well be worth it.
If they never have to use it, in my mind, that would be a good thing.