When writing for children, with children as protagonists, this is especially difficult to work around. In real life, children aren't usually left to their own devices to track down jewelry thieves, mediate social conflicts, run their own businesses or invent extraordinary robots that have the Pentagon calling. No. All too often, there is an adult keeping watch (or guard, depending on your view) and managing everything from on high: the Mom from the Machine. (Yes, sometimes it is the Dad from the Machine, but more often the mom.) So when writing children's fiction there is a delicate balance between plausibility and good plotting.
As Lisa has written previously on her posts on internal v. external locus of control, children must develop confidence in their own agency, their own ability to solve problems, make choices and be responsible for the outcome. The more often the mom ex machina swoops in to take over, the less likely the child is to develop a strong internal locus of control. And just as the deus ex machina solution in a story leaves us feeling rooked, so does the mom ex machina solution in our children's lives leave a feeling of inadequacy in its wake. So often we relish the role of superhero, enjoying the warm glow of gratitude and appreciation and admiration from the ones we've "saved" from a big problem. But unless you are prepared to be lowered from a machine onto your child's stage in perpetuity, you might consider letting your child learn to be the hero of his own story.