Children are not allowed to handle until they are 18 or 21, depending on the church. They are usually sent to the back of the church, sometimes outside, when the serpent boxes are opened. Of course, serpent handling is just one of the Signs the believers follow. They also occasionally handle fire or drink strychnine. Their firm belief is that, if the Lord has anointed them for these Signs, they will suffer no harm.
Snakebites are more common than burns or strychnine poisoning.
Many of these people have done things that many would consider life-threatening, and have come away with no ill effects. As a lifelong Methodist, I admit I have misgivings about their beliefs. But it seems these people are for real. For the most part, they lead exemplary lives. Aside from the Signs, their beliefs are similar to Pentecostal Holiness congregations everywhere.