If you create a new global color swatch, regardless of the breakdown, the name "Black" is automatically blocked. The name "White" is not.

It seems silly to call this issue out, but I've prepared logo libraries for eight and a half years now, and this has been an ongoing consideration. When I create a black swatch, there is always an extra step. Sometimes I intentionally misspell the name to create the swatch, or I create a non-global swatch with the correct name, but in both scenarios I have to adjust the swatch AFTER it is created to produce a black global swatch with the name "Black." The same extra step is not required for a white global swatch with the name "White."

A comparison of my workflow below—

Black Global Swatch:
1. Remove all swatches from the file
2. In the Color palette, click the 'Black' color shortcut
3. In the Swatches palette, either click the 'New Swatch' shortcut at the bottom or select "New Swatch..." from the menu
4. In the New Swatch dialog box, change the default name (depending on color mode, either "R=0 G=0 B=0" or "C=0 M=0 Y=0 K=100") to "Black"
5. Check the 'Global' checkbox
6. Select "OK"
7. No swatch appears in the Swatches palette

White Global Swatch:
1. Remove all swatches from the file
2. In the Color palette, click the 'White' color shortcut
3. In the Swatches palette, either click the 'New Swatch' shortcut at the bottom or select "New Swatch..." from the menu
4. In the New Swatch dialog box, change the default name (depending on color mode, either "R=255 G=255 B=255" or "C=0 M=0 Y=0 K=0") to "White"
5. Check the 'Global' checkbox
6. Select "OK"
7. A "White" global swatch appears in the Swatches palette