Maybe a general idea of some Judges views on tape recordings? Not a recording of parent and child but still an interesting view.
Halston & Halston (2013) FMCAfam 16
32. My greater concern arose in relation to the probative value of such recordings, balanced against the prejudicial nature of a recording where one of the parties to the recording is not aware that the conversation is being taped.
It is a matter which arises all too frequently, particularly in family law proceedings, and seems to have gathered support not only from parties to proceedings but also from legal representatives. It would seem, clearly, to be an evidence-gathering exercise and one that, in my view at least, holds little benefit for the party seeking to gather the evidence, but in fact gives rise to serious concerns as to the behaviours of the party who records such evidence.