your agreement to the terms when downloading the weights is the enforcement - if you grow too big, you become a target from which money can be extracted if you violated the terms.

Contract law covers the use of licensed materials -- The license is the enforcement mechanism. Agreement of the model terms is implied by the use of the model.

If someone were to create a derivative model and distribute that, it would get murky if they licensed it Apache 2.0 or MIT, because users of that derivative would have never agreed to the upstream license (and may not even be aware of it), and the model is unlikely to be copyrightable.