don,
I haven´t said, that 25fps is necessary to use for countries that broadcast in 25fps.
mandatory written down in the BD-spec as follow:
1080p23.98, 1080p24, 1080i30(23.98), 720p60, 720×480 (NTSC-SD).
for these coutries that broadcast in 25/50fps they have extended the BD-specs, so for these countries the hardware must playback 25/50fps as well.
(example): for europe and australia mandatory as well are:
1080i50, 720p50 and 720×576 (PAL SD)
so – if you need to create a BD that should be playable all arround the world, you must use one of the upper framerates and no PAL-framerates.
the all will be playbacked fine on the players over here (I am in europe) as well.
I hope this helps to give you a bit better understanding.
cheers
danny