Comment Naive (Score 1) 505
The entire idea is ill-advised at best, and sophomoric at worst.
It's ill-advised for all the legal reasons others have mentioned above: regardless of my ability to WIN a lawsuit due to misuse of my connection, I'd really prefer NOT to have my equipment confiscated and picked apart in an FBI forensics lab. Oh, and the "bricks through you windows" possibilities suggested in other comments, also strongly encouraging. Thank you for the offer, but no.
Also, the idea that I have *bandwidth to spare* (?!) because neighborhood network segments are "over subscribed" is drinking the telco and cable companies' kool aid. Not during peak usage times, not even remotely. I'm lucky to squeeze out 1/10 my "subscribed" speed. Add the crazy caps on upstream speeds (at least in the US) and one torrent could saturate the connection. Layer on the fact that a working, reliable home network is a requirement for my job.
It's naive to think that "passersby" will be using the network for a quick Google Maps search. Long-term moochers (read: abusers) who actually live in the neighborhood are much more likely beneficiaries. It's also insanely likely the hypothetical passerby, using a device that can access Google Maps, already has a mobile data plan on that device! (Or should, if they don't know where they are on a regular basis...) At SOME point, there are SOME things you probably just need to grow up and pay for.
(NB, I may be especially jaded because my neighbors won't scape their dogs' crap off the sidewalks, much less respect my digital real estate, so I'm perhaps much less inclined to think this is a good idea than I would otherwise...)
Now, bring me a case of an under-served / low-income / rural area, where broadband penetration is already awful, and you *might* have a chance of convincing me. Although in that scenario, there's a better case for larger-scale intervention, i.e. a partnership between providers and local government, which would probably be a necessity to even get the infrastructure into the area to start with.