1. A biometric authentication system comprising: a biometric image sensor in an operative position with respect to a mechanical switch on a host electronic device and configured to sense biometric characteristics of a biometric object while the biometric object is operating the mechanical switch, the operating of the mechanical switch providing at least one of input and control to the host electronic device; and wake on event logic cooperating with at least one of the biometric image sensor and the host electronic device and configured to at least delay any response by the biometric image sensor or the host electronic device that increases power consumption by either the biometric image sensor or the host electronic device, beyond that needed for the performance, by at least one of the biometric image sensor and the host electronic device, of a bona fides analysis of an object being sensed while operating the mechanical switch, until a positive completion of the bona fides analysis determines that the object being sensed is an object desired to be sensed to perform a user authentication.