I don’t know if I told this one before: My sister met a missionary once who felt called to minister to the tribes of Burma. Burma was then, as now, pretty much a closed country and foreigners were not welcome–especially foreign missionaries. This fellow would cross the border through the jungle and try to meet up with the nomadic tribes and share the gospel with them before going back to safety across the border.
One time he was caught by the local militia and thrown into a well in the middle of an abandoned village to starve to death. He knelt there in the mud–a modern Jeremiah–wondering how he would ever get out. He called for help for hours and no one replied. 
The next morning he looked up to see a man in a white linen suit looking over the edge of the well. He spoke to him in English and asked if he could help. The missionary was surprised to see the man lower a rope and haul him up. The white suited man with the British accent took him to the trail that led back across the border to safety and wished him well.
In subsequent visits across the border, and in the border towns he looked for the strange Britisher. He never found him, and furthermore, the border guards had never seen such a character, nor had anyone in the Burmese jungle ever heard of him.

The nagging question is, if we all have guardian angels, why do we still have accidents and hurt ourselves?  Well, first of all, the angels are limited in how much they can help if we do dumb stuff. Why should an angel save our skin if we’ve been drinking too much and fall down the stairs? Secondly, maybe they do save us more than we know, but the fact that we didn’t have that accident, did look up in time to see that oncoming bus, and did stop the car in time meant we didn’t have the accident, therefore we don’t know that the guardian angels saved us.

Still, there remains the question of why bad things still happen–especially to children. We don’t know. There are so many complicated factors in any one event that we perceive as an accident. We don’t know the powers of the evil ones on the other side, we don’t know what human evil is behind ‘accidents’. Perhaps there is only so much that our guardian angels can do, after all, they are not omnipotent, and even they cannot over-ride the human will.