Theoretically. That feature's been announced, not shipped. Don't be so quick to rule out privacy concerns on a feature that no one's used.

This doesn't necessarily need to be a privacy concern so much as a user experience concern. She's his wife, not some random stranger on a bus. There's the user experience of being able to hand your wife your tablet and have her be able to pull up her own Gmail in a native app without a bunch of reconfiguration of settings.

The feature won't be available for phones.