I think the constitutional claim is a weak argument, but the NCAA was successful using the same line to attack a Nevada regulation that required the NCAA to do certain things whenever it was punishing a Nevada member. The big difference here is that California is not regulating the NCAA the way Nevada tried to do. It's only regulating schools within its state and not placing a burden on the NCAA. Practically we know that the NCAA will feel pressure here to change its rules, but neither it nor its non-California members are being forced to do anything. Oddly enough, I think California's action here is likely to be appealing to both conservative and liberal judges - for very different reasons - and that will make the NCAA's constitutional challenge even more difficult. It all becomes moot, anyway, if Congress takes similar action to California, and it looks like they may.