This would be less beneficial IMHO on a phone. My wife sometimes uses my phone, but she always has her own nearby. when she is using it, its for a quick, specif

This would be less beneficial IMHO on a phone. My wife sometimes uses my phone, but she always has her own nearby. when she is using it, its for a quick, specific reason. But I could really see this on an iPad. iPad's are often shared around a household, this would be amazing for that. Macs themselves would also apply here.