In 2005 people panicked and evacuated large parts of Houston days before Hurricane Rita was even thinking of moving in that direction. Rita ended up not hitting Houston (shocker), and the evacuation killed more people and caused more problems than the storm itself. Needlessly calling for evacuation beyond 72 hours is a highly risky event. Rest assured, emergency managers are going through their 5 day pre-landfall checks and if evacs are needed, they'll be called for. You cannot force people to leave though, only renters on coastal properties.