I leave my wifi open because I like being a nice neighbor. A little QoS and a firewall for my home network, and you're free to connect.
Also, read https://www.schneier.com/blog/archives/2008/01/my_open_wirel... as linked below in this thread.
Computer forensics would be required to link the requests to a specific computer and person. Your ISP is probably still free to just ban you though.
Just sayin' ...
http://www.gamepolitics.com/2014/03/25/florida-judge-rejects...
http://securitywatch.pcmag.com/security/297475-ip-address-no...
http://blog.ericgoldman.org/archives/2011/10/court_nukes_ano...
P.S. Downvotes on HN do not mean "I disagree".