Man, I did a double take on the thread title, at first I read wifi as wife. I'm not stealing just borrowing for about 10 minutes...whoops didn't even take that long.

Borrowing/using a neighbor's property without their consent or acknowledgement is wrong. Yes, it's piggy-backing on a signal and usually doesn't affect the owner's use, but that's a slippery slope of a justification. Your friend is in double jeopardy because he's not supposed to be online as a disciplinary restriction...in for a penny in for a pound.

How far does a signal typically reach? I don't have mine password encrypted because we live in an area with just one neighbor who is within 75 feet of the house; all the rest are 200-300 yards distant.