How is it "always best to provide a license"? I've heard the argument that a contrivance like
the three-clause BSD ensures that the code is available even in states which do not recognise
public domain, but I've never heard of anyone who experienced this difficulty.
SQLite is also PD and has considerable uptake in large free software projects, commercial
endeavours and in US government software. It doesn't appears to have been hindered by being
PD. Do you have anything to back up your claim that it would have been "simpler", and that it
would have "avoided needless confusion", by picking a contrived set of terms instead of a
perfectly valid copyright status enshrined in law?
Furthermore, BSD explicitly ties a work to an author. Perhaps this was the precise reason for
choosing not to hold copyright over the work in this case.