I would love it if I could get away with not allowing him to play with my phone. It simply is not possible. If you have a child you would understand. They want to play with your phone. You can give them their own tablet, which we did, a Nabi 2, which is pretty nice. They still want to play with your phone. There does not seem to be any way to get around this. Children want to play with mommy and daddy's iPhone. I agree it is bad practice, but I cannot simply say no, because then they want to play with it even more, followed by temper tantrums. Which takes us in a whole other different direction about disciplining children.
The iPhone can also be used as an incentive for a child to behave. I.E. if you behave at "X" then you can play with the phone. This actually works. The phone can entertain a child almost endlessly, a huge plus when you are out and your child is "bored" or misbehaving. Parents know what I am talking about here.
Let's not get into what we should and should not do for our children, instead, let's have a phone that can handle this situation.
Let's take this off the consumer and put it on Apple to write a few lines of code.
Lastly, even if I take it away from the child permanantly, the girlfriend issue described above is still present for when she "just needs to make a phone call since her phone is dead" and then proceeds to go into your email and start snooping around, etc. Not that there is anything to find there, it just makes me uncomfortable that anyone that can get into the phone for whatever reason (like borrowing it to make a phone call) can then just get into whatever apps they want.
I'm surprised no one has said, "yes this issue has happened to me too". Am I really that special?