So, this is an interesting theory.
However, I have personally seen Facebook posts (some of which were later deleted) where people had mentioned sub-contractors having not been paid. Some of these by people purporting to be spouses of contractors etc.
Yes, I know Facebook is not a reliable source, and I don't have a documented reference to any of these; but I saw enough of them to give me confidence that there are some super unhappy contractors out there.
So liens can be placed on the ownership properties by sub-contractors if the main contractor was supposed to pay them because technically it’s the property owner to ensure everyone is paid.