Its legal to make a duplicate. It isn't legal to sell it! You will be infringing Intellectual and Copyright for the owners in many cases and re-casting costs business and sculptors jobs so please.. be sensible.
So that aside, it is quite nice sensation when you manage to get a mold to work properly but it is a lot of energy and frustration when you get an air lock or bubble that ruins are part..
With 3D printing coming along and getting cheaper and cheaper, this old fashioned method will fade I suspect in popularity. Especially when high def 3d scanners become cheaper.
But in the meantime.. watch and enjoy:
