you know what turbo69stang...I totally agree with you, whats the worst that can happen by asking the owner...except maybe some buckshot up the wazzoo...lol just kidding and your right about asking 1st.
It would be easy to steal.. Even some old cars that I have seen, but we must respect the wishes of others. If someone wants to let a car rust or a sign stand tall its thier choice. I always find a owner and ask. whats the worst they can say F you get outta here!?
Looks like the grass is cut and the owner is aware its there. Just enjoy it.
Hopefully noone janks your ride.