Exactly ... he's using somebody else's property, without their permission. There's something ironic about that "NO TRESPASSING" sign ...
Also, this has the potential to be serious ... if the owner doesn't take action against him, he could eventually assert "adverse possession" against them and take the property.
“he could eventually assert “adverse possession” against them and take the property. “
It appears the property belongs to the City so adverse possession wouldn’t apply here.