I have an open access point on my home network. I have the guys in my company's internet security team try to crack in to my home network about once a month, when they happen to be coming over for a party or some other activity. I don't mind if people connect and use it for whatever reason. I have QoS restrict the usage to about 15% of the total if it ever becomes an issue.
Our local grocery place just started advertising they have an open access point. After lunch today I tried to connect when I was close in (about 3 spaces back from the store front) and lo and behold, I can connect.
I don't break the TOS with my isp and I'm not breaking the law by connecting from my car to the open access point at the grocery store. If someone has an open access point, I can only guess they wanted it that way and I don't have any moral issue using it. It's not like I'm trying to hack into their home network. I could care less what they have there. I'm interested in connecting to the internet, and that's all.