Luke, IANAL but AFAIK the font exception is merely a *clarification* that using this font in a document does not constitute a derivative work but is merely "use" of the font so the document itself need not be GPL-ed. This is however true even without the clarification being explicitly stated and so you can perfectly use a GPL-ed font without any problems.
See also the Linux kernel GPL clarification which states that using a program using system calls provided by the kernel is merely "using" the kernel and is hence not a derivative work thereof. Sent from my Android phone
