>If the the cafe owner didn't mind how can this be offence??? Shocked
Because it was in America LOL
State laws over there make our daftest laws look sensible
http://www.foxnews.com/story/0,2933,276720,00.html
OK, but reading the full article this can almost be classified as 'freak accident'... 
You really have to be extremely unlucky for this to happen to you. :-?
Actually this has happened in the UK too, struggling to find the link though.....will keep searching
bit older than I thought http://www.telegraph.co.uk/news/uknews/1548960/Two-arrested-over-wifi-theft.html
Not so fast there...
1. This was 'theft' from private home connection, and it can understandably be alarming if someone piggy-backs on you home network without you knowing. A coffee-shop network is intended for customers use, so while technically an offence to use it if you are not a customer, it is not really the same as the former.
For example: if someone ;eaves their front door unlocked, and you open it and walk into their home, or if you go into the kitchen of a coffee shop in spite the fact that it is marked 'private', it is an offence in both cases but far from being the same...
2. You really have to be unlucky... if the users switched-off their laptops when approached by police, I doubt if the police would have gone all the way into forensic IT to check what they were logged into... it is more likely that they honsetly replied to police questions saying they logged-in to unsecured connection.