We had our wireless internet zapped by lightning on a Friday. Didn't realize this till we fired up the computers on Sunday am. We have a stash of blank name tags on hand as well as index cards. We had our leaders create random security numbers (like F1's) and used the index cards. While leaders were creating security cards I ran to my office and exported names to excel. We ran a report and exported the kids names to excel and sorted by family name. I chose sort by family name so we could still give each family one security card vs. if we had sorted the kids by their last name.
We had to do this for 2 weeks. Our internet in our kids building had to be re-configured and some equipment re-installed.
Depending on the size of your church this might work as a possibility for you. We explained to our parents what was going on and most were very understanding. They have a greater appreciation for our self check-in stations now!