Ask HN: Deep learning model license enforceability

When source code is licensed under an open license, you can't use it without complying with the license due to the fact that otherwise you will be infringing copyright.

What about model weights? My understanding is that model weights aren't copyrightable (is this really true?). What makes it obligatory for you to follow the license? Some providers, make you accept a license before you could download anything, but what if it's freely downloadable? (I am pretty sure that there's something which let the license be enforced, just want to understand how it all works).

P.S. I am not a lawyer.