>The scope of the Unicode Standard (and ISO/IEC 10646) does not extend to encoding every symbol or sign that bears meaning in the world.
>This list has been round and round and round on this -- regular as clockwork, about once a year, the topic comes up again. And I see no indication that the UTC or WG2 are any closer to concluding that bunches of icons should start being included in the character encoding standards simply on the basis of their being widespread and recognizable icons.
>Where is the defensible line between "Fast Forward" and "Women's Restroom" or "Right Lane Merge Ahead" or "Danger Crocodiles No Swimming"?
(http://www.unicode.org/mail-arch/unicode-ml/y2005-m08/0371.h...)
Now it looks they add whatever somebody thinks of. I guess it's related to the liberation from the BMP.