Some publishers do try to offer contract for all rights worldwide these days. Gollancz made a big thing of offering a flat million sterling for global rights for the next ten Alastair Reynolds books, for example.
This generally looks like a bad idea from the author's POV, as from the moderately successful mid-list genre authors I know well enough to be able to tell, foreign sales consistently bring in somewhere between as much and twice as much overall per annum as initial sales.
Policing what gets sold in which domains, in this day and age, looks like being pretty much impossible to do with any absolute force.