Not related to armed security per se, but my church has an outstanding child care/Sunday school checkin program. You sign up for it at the front desk, they photograph you, your child, and everyone authorized to pick up your child, and take fingerprints of everyone who can pick up your child. When you drop a child off, you scan your fingerprint, scan a pager from a bucket, and log your child in. A label printer runs off a 3" x 2" form-feed label with your child's name, photograph, and mini photo and name of everyone authorized to pick him or her up. A duplicate of the same form prints off on a receipt. You stick the label on your kid's clothing, and hand the receipt to the volunteer in the child's room, and the volunteer checks that the names and photos match up. Same thing again to pick a kid up.
GREAT system. Granted, it's a large church that due to its membership demographics also has a lot of money, but I'd say the money and thought they put into their nursery system was prudently and wisely spent.
On the armed security note, I volunteer at a different church that hosts an interdenominational lay counseling center. All the churches in the area, most of the social welfare agencies, local law enforcement, and both major hospital organizations where I live refer people to the counseling center. The clinical director is a member on this forum and encourages his security volunteers to be armed. At this point, that security team is only for the Thursday nights when counseling sessions are run at the church, but I think people at both churches would be surprised at how many armed permit holders and off-duty police officers are in any given service there.