If it's a child sitting on the lap with her father, and her father is related to Hezbollah (and as such carrying a pager), this stuff could happen, I think.
All in all horrible to be honest ...
Apparently a message was sent to the pagers right before exploding. I saw in a couple videos where the victim looked down at their hip and angled it to see the screen. It makes sense as a trick to ensure the target is close by when it goes off, but a kid could just as easily pick it up off a table after hearing it buzz.