It's not a bug, it's a feature. ;-)
It so happens that yesterday I was wondering about the very same problem. I then resorted to the official PDF specification as published by Adobe. And there (adobe.com/devnet/acrobat/pdfs/PDFCreationSettings_v9.pdf#page=36) I read:
"The following table identifies the types of fonts that you can (or cannot) embed or subset through Distiller settings.
Distiller control over embedding and subsetting fonts:
================== ==================== ============= =====================
Font? NeverEmbed? AlwaysEmbed? Subset?
================== ==================== ============= =====================
Type1 Yes Yes Yes
Type3 No (always embedded) - No (always subsetted)
TrueType (Type42) Yes Yes No (always subsetted)
CIDFontType0 Yes Yes No (always subsetted)
CIDFontType1 No (always embedded) - No (always subsetted)
CIDFontType2 Yes Yes No (always subsetted)
OpenType Yes Yes Yes
For additional information on Type 1, Type 3, Type 42, and CID-keyed fonts, see Chapter 5, “Fonts,” in the PostScript Language Reference and Chapter 5 in the PDF Reference. You also can find additional documentation on fonts
at the Acrobat Developer Center.
"Note: Distiller 5 and above also support OpenType fonts; Distiller 4 does not. OpenType fonts are based on the compact font format (CFF). For more information, see the Compact Font Format Specification at the
Acrobat Developer Center."
So this explains it all:
According to the official Adobe specification...
- ...Type3 and CIDFontType1 are always embedded, even if you set a fontname which happens to be
one of these 2 fonttypes to "Don't embed" ;
- ...Type3, TrueType (Type42), CIDFontType0, CIDFontType1 and CIDFontType2 are always subset,
even if you set a fontname which happens to be one of these 5 fonttype to "Don't subset".