Yisro

Rashi (Shemos 20,13) says that Lo Signov is reffering to kidnapping. But why isn't it called Lo Sigzol? Its only Genaiva when the party being stolen from is unaware that they're being stolen from! In a standard case of kidnapping the victim is well aware that they're being kidnapped. If so, it should be gezaila (as gezel is when victim is aware)!