Are there ever any practical reasons for purchasing an explicit license to "public-domain" software, assuming both the software developer and the user reside in jurisdictions where the public domain is recognized?
As an example of this, Hwaci, the company behind SQLite (which is famously dedicated to the public domain) offers 'warranty of title' licenses for sale costing US$6000 each. These are the reasons they offer for purchasing a license:
- You desired warranty of title and indemnity against claims of copyright infringement.
- You are using SQLite in a jurisdiction that does not recognize the public domain.
- You are using SQLite in a jurisdiction that does not recognize the right of an author to dedicate their work to the public domain.
- You want to hold a tangible legal document as evidence that you have the legal right to use and distribute SQLite.
- Your legal department tells you that you have to purchase a license.
I can understand why someone residing in a country that doesn't recognize PD might want to buy a license, for legal certainty. But for someone residing in e.g. the United States where the public domain is defined, the only one of these points that makes sense to me is the last one, "Your legal department tells you that you have to purchase a license" which is trivially valid if that's a company policy and the money is inconsequential anyways.
I'm particularly curious about the first bullet point, because it's not clear to me what practical rights 'warranty of title' provide, and whether or not they are already provided via the public domain. And aren't all of these rights mitigated just as easily due to the public domain, because Company A could always craft their own license granting themselves these rights (given that they have no more or less rights than Hwaci on the original code to begin with)?
So my question is: What are the practical reasons (if any) for why a U.S.-based company may want to purchase a license to public domain software like SQLite?