The answer to that is “But maybe the parents are misinformed about the tooth fairies’ abilities?” You can go on and on like this, but at this point I would stop praisuing the child for pursuing the ratinal method for solving problems, and strat educatting the child in the next lesson of rationality: 0 and 1 are not probabilities, all knowledge is probibalistic, and you need to do VoI calculations before rushing off to try to rule out narrow and increasingly unlikly options.
The answer to that is “But maybe the parents are misinformed about the tooth fairies’ abilities?” You can go on and on like this, but at this point I would stop praisuing the child for pursuing the ratinal method for solving problems, and strat educatting the child in the next lesson of rationality: 0 and 1 are not probabilities, all knowledge is probibalistic, and you need to do VoI calculations before rushing off to try to rule out narrow and increasingly unlikly options.