sorry i forgot the links mentioned:
http://certifications.wi-fi.org/wbcs...d_products.php
well basically it is illegal because you are connecting a link which is not yours.. however our instinct would tell us to connect because why in hell they leave it open and unsecured in the first place... anyway, that depends on the local ordinance where you are residing... but again as ive said, they have inability to determine your identity becausethey can only see your pc's mac/ip addresss unless they have to get into your house (which is agianst your privacy) and check that you are using that ip/mac address