Okay your in your home, you have your iPhone and you 'see' a Netgear 42 or do you OWN a Netgear 42. If you 'SEE' a Netgear 42, that is someone's router 'broadcasting' it is available to use for that person's family, NOT YOU. Be like the person started the car in the driveway and left the car door open to run inside to get something, does that mean they are giving you the car to drive? NO, it would be and using the Netgear are both theft.
Now if you OWN the Netgear inside your house, uhmmm.. you bought the netgear to make a wifi connection why wouldn't it be safe to use? You spent the money to get one?