The most essential point I need to ask of you is this: if it is filming in "secret", how come you know about it ?
Undercover filming in the workplace and in the street goes on all the time whenever a "whistleblower" has complained to the media, for example, in filming behind the scenes in restaurant kitchens (for matters affecting poor hygene about which the public should be made aware), or in care homes (where there may have been an allegation of ill-treatment of an elderly patient by a member of the staff), so I fail to appreciate what all the fuss is about in the circumstances about which you show concern.