Like what does "money laundering" look like on the ground, how would I know if someone around me was trying to do that? Restaurants in high rent areas offering

Like what does "money laundering" look like on the ground, how would I know if someone around me was trying to do that? Restaurants in high rent areas offering suspiciously cheap food with relatively few customers. They are all over NZ. People are so naiive about what they are.