If people are going to get pedantic with you guys, they’d better at least be right. Hama explicitly says that bloodbending can only be done under a full moon. When Katara bloodbends the wrong dude on the Southern Raider ship, it is night time, and there is a full moon out. When she attacks her mother’s murderer, it is day, but she doesn’t bloodbend. She just nearly skewers him with a dozen or so razor sharp ice spears.