[tz] Theory - proposal to delete the reference to population

[David Patte]

International law says that any nation has the right to enfoce its own 
laws within its own territorial waters (12 nautical miles?), which 
implies that a nation COULD enforce timezone laws within its territorial 
waters. Many nations encourage it, but don't enforce it. For signatories 
of the UN Law of the Sea, which is almost everyone except the USA, 
nations can ENCOURAGE that that their laws be applied as far as 200 
nautical miles.

But whether any nations enforce timezone laws within territorial waters 
is up to each nation.

But it is certainly common practice to use port time when docked at port.

See also:
http://en.wikipedia.org/wiki/Territorial_waters