see my replay above, if it's not password protected, it's accessible, simple as that. in this day and age the "stealing bandwidth" is just not an issue. I think a better way to look at is like this..Using your garden house..
scenario a: the house is locked, but you break the window and grab something...obviosly this would be breaking/entering, burglary etc.. or hacking.
scenario b: the house is locked, the windows are are locked, but the curtains are open, you peek in , have a look and leave..no harm no foul.