Thanks for all the comments. I guess what I'm really asking is that those people who like to embed fonts consider having a part of their CSS does not embed the font, and which is commented out. I could then go in with my HTML editor, remove the comments, and comment out the embedded text. I've seen some style sheets which are really hard to follow.
And thanks for the mention of tweak_epub and CoolReader3. I'll definitely check them out.