Lawmakers in Colorado have been asked to consider a bill that would bans law enforcement drones from gathering facial or other biometric data unless a warrant has been served.Introduced by State Senators Linda Newell and Kevin Lundberg, the Senate bill would require law enforcement to obtain a warrant before any use of a drone, although one could be obtained during specific emergency circumstances.”The law enforcement agency using the unmanned aerial vehicle shall not use facial recognition or other biometric matching technology on nonsubject data collected by the unmanned aerial vehicle,” writes the bill.Drones are becoming increasingly available at every level, and when it comes to government use, it needs to stay within the 4th Amendment,” which guards against unreasonable search and seizure, Lundberg told CBS.Democratic Senator Lucia Guzman of Denver, said the state needed to protect citizens' privacy. “Whether it's the police or the FBI or my parents checking on me without my knowing it, I want to know my privacy is protected,” she said.Last November, the American Civil Liberties Union has said that new surveillance technologies such as facial recognition should be reviewed by the US public before being deployed by law enforcement authorities.The ACLU calls follow an uproar after the San Jose Police Department quietly obtained a drone in August without consulting the public on any related policies and procedures.