If they have it in an area where it could get leeched off and don't take the proper measures to secure it, they have no one to blame but themselves if someone uses it.

please vote too

Well, If your neighbor is unaware of your "leeching", it's wrong and would get you a black eye and a broken rib, would that neighbor in question be me.
However, 2 of my neighbors share my connection, with my permission and a small fee. Each gets 1 meg down for $5 (they don't need or want more) and both have secure, password connections thru my wireless router. Only rule is no morpheus or kazaa.

My point is, you'd be suprized how many reasonable people actually exist. If you ask your neighbor, he might agree to a similar arrangement thus canceling out your moral dilema.

However, if you're screwing over your cable/DSL company out of profit and contol, you have a beer on me anytime

*edit*
NVM, just re-read your post.
Go for it...it's not coming out of anyones pocket.

You might be breaching some of the terms and conditions. Many ISP's have something about it be used in one property only. That's not particularly major though.

Internet access will be free in some years anyway. (or so i like to believe...) Thats how it should be. And using an unencrypted access point is a grey zone in legal matters (unless they changed it since i last checked) so, nobody could get you for that if you have a good lawyer. (depending on the "use" of the connection...) Tho I would ask if it's a private user.