If you dream of observing an illegal act, then you must remember the feeling you had while you were dreaming about this act, since this can give clues of hidden guilt due to past actions that you might have. But if you dream that you are the one committing illegal acts, the dream is showing the need of liberation from social molds, or perhaps the lack of adaptation to the environment around you.
Illegality dream meaning
Read more about dreaming of Illegality in other dream meanings interpretations.