In a situation like this common sense should prevail. Sneak some bolt cutters in some big bag and cut the damn cable.

IF a bike is setting somewhere with flat tires, it hasn't moved, and it's not private property then by all means, keep this bike from the trash.

I think most of these bikes deteriorate in the weather until they are completely scrap, then they are trashed, costing the authorities money. Instead they could be claimed and used. THe choice is clear.