隨便錄人音算唔算犯法？

In Hong Kong, regardless what purpose, recording is not violate any law at all except you are recording copyrighted items.

However, as other suggests that the recording may be admissible in court. This is incorrect because you must have authoriztion in order to record for evidence.

Remember Eason Chan's father got caught in his money counting money? ICAC has gotten a warrant and a consent from the Housing Department to do so.