The present work tries to expose arguments that allow to discard the main arguments that are put forward to consider the surreptitious recordings of the worker of which he is a participant as illicit evidence. To do this, we will start from the consideration of the right to evidence that is part of the right to defense, then we will analyze what was resolved by the Supreme Court in the so-called BCI case on the restriction of the causes of illegality to that obtained with violation of fundamental rights. We will then analyze the main arguments other than the violation of the right to privacy that are invoked in favor of illegality, to finally analyze the possible violation of the right to privacy and the formula that the Supreme Court used in the BCI case. for the correct resolution of these cases, centered on the doctrine of legitimate expectations of privacy. Finally, we will analyze the possibility of predicating the legality of the recording even in the presence of a legitimate expectation of privacy