One day, a voice talks in the head of every human...
Cue in the Pandem novel. There, humanity makes contact with eponymous god-like creature (while it is implied that it evolved alongside humans or is something unknowingly created by them, its origins are unclear). At first, Pandem tries to help humanity as much as it can, preventing natural disasters, cancelling death, providing means of communication and entertainment. But after some time (spoiler!) it realises that it does not do humanity a favour. Humanity is now relying too much on Pandem and is not progressing. Thus, Pandem slowly pulls back to leave humanity to its own devices.
At some point in the novel, Pandem is still canceling accidents involving children, but not anymore accidents with adults. The prevention of accidents happens with slight, very minor changes to reality, e.g., a tire does not slip, while it rather should have. As Pandem is something god-like, it can pull it off. Basically, any accident, a car crash would still happen, if the passengers are all adult, but it just would not happen in exactly the same circumstances, if a child is on board.
Right in the novel, there is an exploitation of this behaviour. Some people willing to drive recklessly, but not willing to die, just take some kid of a spin, for an assurance that no accident will happen. As Pandem (spoiler!) is still pulling back slowly, at some point the exploitation will stop working, as kids would die, too, in car crashes.
Now, to your question. A god-like creature with power to alter reality / play with probabilities / etc. can just pick such variants of reality where kids do not die.
At least in the above case it does not prevent exploitation (even a much milder as you described). Basically, tying a kid to a battering ram can mean direct harm to the kid – and hence god's wrath is on those guys with the ram. People driving recklessly with a kid in their car might be exploiting a loophole, but do not mean to harm the kid (at least not more than themselves if Pandem looses it).
I would recon that "immutability" / canceling disasters can be done on some kind of an "autopilot". But solving ethical dilemmas rather cannot. Also, there would definitely be some rather unsolvable ethical problems.
Basically, I see the applicability of physical immutability (duh) a rather easier problem as compared with the ethics of such immutability. I would guess that your deity would not simultaneously speak in the heads of all people of the planet (just the thing Pandem did!) to say "for the next five years the kids up to 14 years get no harm, but everyone else does as it always have been". Even communicating the general rules might be a problem. Indicating that the deity would be displeased if the rules are circumvented, played around or exploited still falls under communication.