while you may not intend so, to use another person's internet access account without their permission is technically illegal.
HOWEVER..... what must be understood, is that that the door of the trap looks just like the other door.
It is possible to put one's machine and info at risk by accessing someone's (who we do not know) network.
By virtue of the fact that we are on someone's network, they could access us, at the same time, and if we are not configured otherwise, would not know.
It has been prosecuted successfully, so nowadays, using free access points has been something of a different tact, to do so without unforeseen consequences.
"Wardriving" is the act of cruising commercial / business areas and finding unsecured networks.
In Europe, people would leave little marks of chalk"Warchalking" on the sidewalk indicating network Signal Strength, direction, etc.
http://en.wikipedia.org/wiki/Wardriving ... ggybacking
http://en.wikipedia.org/wiki/Piggybacki ... _access%29
