This expression has become popular to warn of the less obvious results or effects of a situation or event. It is based on the fact that only ten percent of an iceberg is above the surface of the ocean. According to the Merriam Webster dictionary, the expression became popular beginning in 1969. In my personal opinion, “Tip of the iceberg” could be used to predict unintended consequences that often show up when the government tries to solve a problem with complicated laws.