I think it depends on what you do with someone else's connection. A criminal could definitely get an innocent person's house raided, but cops aren't stupid either. If they do their homework first and see Aunt Mildred only goes to facebook and cooking-network.com, and suddenly she's sending death threats to public officials, they might knock on her door and politely ask to put a wifi surveillance device in her home to pinpoint the intruder's signal.

Sure you could steal signals or go to starbucks (which has cameras of course ) a few times and maybe get away with it, but to do it reliably, on demand, is very difficult.