Interesting. I would compare this to walking into an unlocked neighbor's house where the door is wide open. Might be trespassing, but it ain't breaking and entering.
Back when I was using a wireless router, I had the encryption enabled to prevent this kind of thing. Just like we keep our front gate locked.
If you don't want someone using your network, lock it!
None of the analogies apply. It's more like offering a telephone in a condo and expecting people to NOT use it. I did NOTHING to access the signal. It was simply there.
I think it is the restaurant across the lot. It's a bad signal.