WHAT YOU SHOULD KNOW ABOUT USING SPY CAMERAS
Spy cameras are useful in investigative journalism and for anthropology studies. But before you go around carrying your spy camera, you must first familiarize yourself with the law and film restrictions.
Every place has their own laws regarding the use of covert surveillance camera, or spy cameras. The majority is that you are allowed to use them in your own home and in public places such as the shopping mall, stores, restaurants and parks without needing to inform others. For public, it is legal as long as it is not directed at a specific person from inappropriate angles (i.e. filming under skirts).
Spy cameras are not allowed in areas where there is an expected level of intimacy such as in bedrooms, bathrooms, changing rooms, locker rooms and so on as it violates the voyeurism legislation. And if you are renting out your property or home you are obligated to disclose any recording devices to your guests and take them down. It may be legal for you to put up cameras in non-private areas of your home but not when renting it out. They become the residents of the home whether they are renting for short term or long term. Leaving cameras on without their knowledge infringes on their right to privacy.
You must also recognize the different laws regarding the recording of video and audio footage. When recording videos, you may not be obligated to disclose the use of spy cameras in most public places. But there are states and countries with the two-party consent which requires that everyone must be informed of the audio recording. Secretly using microphones is illegal and may fall under wiretapping. That is the reason why a lot of nanny cams are built without microphones.
Of course, there are exceptions though with the laws about audio recording. You may still use surveillance camera with microphones for home security purposes and trespassers or burglars are not protected.