Aren't home networks password protected, or are many too lazy or technically challenged to use a password.
I can get up to four wireless networks in the neighborhood and mine is the only one secure. I mentioned to my next door neighbor that I could get into his computers and check out his files if I wanted to and that if I could, anyone could. He said, there's not a lot there to look at so he doesn't care. Guess that's a lot of people's attitude.
MOST people don't lock down their wireless routers. I blame Linksys and NetGear for making products that are "plug and play" for networking.
Granted, with a few Linux tools, anyone could sniff wireless networks, even SSID-disabled networks, and get on them with a password sniffer (authentication is passed in plain-text).
If you have a home router, at the least change the access password to it. I'd suggest turning off the SSID and turning on WPA-Personal encryption through TKIP. This will keep most prying eyes out, but if someone really wanted to hack into your network, it doesn't take much.
Roughly two-thirds of all home networks are not secure in anyway. It's also true that anyone that is "determined" can break basic WEP encryption fairly easily.
Consider that the Library doesn't nominally allow use after hours - therefore, his use was using their hardware when it wasn't allowed to be used by the public. Technically they've got him. If the police gripped about it while the library was open I think he would have a leg to stand on. The other issue is that this guy has been going around town doing this and looking suspicious. He has become a nuisance to the cops - (at least the third time they've been called on him..) So they took action.
When the totality of the situation is considered I think the cops were reasonable.
So if a homeowner leaves his front door unlocked, does that still make it legal for someone to come in and steal something from the house?