Clearly, here, this was not observed. Safety starts and ends between your ears.
The kid may have been on the other side of the house, so without knowing the facts it is hard to state that negligence is a factor.
I have a bunch of 700's and have modified them all to remove the bolt lock. The only thing between you and an accidental discharge is 0.030" of sear engagement, and less if sear return is hampered by some crud or congealed grease in cold weather. The Remington safety, being a trigger-blocking safety, is inherently not as safe as a firing pin locking type like a Winchester M70. Unfortunately, M70's are not as accurate a design as the Remington (no flames, please...you never see Winchesters winning benchrest matches, but Remingtons are common). Winchesters feature a middle safety position to allow unloading without disengaging the firing pin lock. Much safer.