Font matching with @font-face rules containing invalid data

In each of the rules below, a sans serif font is specified as a downloadable font, with fallback to a serif font. The cases in red below represent situations where user agents don't agree when testing with IE10, FF trunk, and Chrome dev.

@font-face {
  font-family: test1;
  src: url(fonts/sourcesans/SourceSansPro-Regular.woff);
}

#test1 { font-family: test1, serif; }
Fantastic!
@font-face {
  font-family: test2;
  src: url(fonts/sourcesans/SourceSansPro-Regular.woff);
}

@font-face {
  font-family: test2;
  src: url(fonts/sourcesans/SourceSansPro-BlackIt.woff);
  font-weight: 900;
  font-style: italic;
}

#test2 { font-family: test2, serif; font-weight: 900; font-style: italic; }
Superb!
@font-face {
  font-family: test3;
  src: url(fonts/sourcesans/SourceSansPro-Regular.woff);
}

@font-face {
  font-family: test3;
  src: url(fonts/not-a-font-no-sir-no-way-no-how); /* not found */
  font-weight: 900;
  font-style: italic;
}

#test3 { font-family: test3, serif; font-weight: 900; font-style: italic; color: red; }
Splendid!
@font-face {
  font-family: test4;
  src: url(fonts/sourcesans/SourceSansPro-Regular.woff);
}

@font-face {
  font-family: test4;
  src: url(fonts/sourcesans/SourceSansPro-BlackIt.woff) format("bogosity");  /* bad format hint */
  font-weight: 900;
  font-style: italic;
}

#test4 { font-family: test4, serif; font-weight: 900; font-style: italic; color: red; }
Fabulous!
@font-face {
  font-family: test5;
  src: url(fonts/sourcesans/SourceSansPro-Regular.woff);
}

@font-face {
  font-family: test5;
  src: url(fonts/sourcesans/SourceSansPro-BoldIt.woff);
  font-weight: bold;
  font-style: italic;
}

@font-face {
  font-family: test5;
  src: url(fonts/sourcesans/SourceSansPro-BlackIt.woff) format("bogosity");  /* bad format hint */
  font-weight: 900;
  font-style: italic;
}

#test5 { font-family: test5, serif; font-weight: 900; font-style: italic; color: red; }
Stupendous!
@font-face {
  font-family: test6;
  src: url(fonts/sourcesans/SourceSansPro-Regular.woff);
}

@font-face {
  font-family: test6;
  src: url(fonts/sourcesans/SourceSansPro-Black.woff);
  font-weight: 900;
}

@font-face {
  font-family: test6;
  src: url(fonts/sourcesans/SourceSansPro-BlackIt.woff) format("bogosity");  /* bad format hint */
  font-weight: 900;
  font-style: italic;
}

#test6 { font-family: test6, serif; font-weight: 900; font-style: italic; color: red; }
Amazing!
@font-face {
  font-family: test7;
  src: url(fonts/sourcesans/SourceSansPro-Regular.woff);
}

@font-face {
  font-family: test7;
  src: url(fonts/sourcesans/SourceSansPro-Bold.woff) format("bogosity");
  font-weight: bold;
}

#test7 { font-family: test7, serif; }
Exceptional, but strange...
@font-face {
  font-family: test8;
  src: url(fonts/sourcesans/SourceSansPro-ExtraLight.woff);
  font-weight: 200;
}

@font-face {
  font-family: test8;
  src: url(fonts/bogus-url);
}

@font-face {
  font-family: test8;
  src: url(fonts/sourcesans/SourceSansPro-BoldIt.woff) format("bogosity");  /* bad format hint */
  font-weight: bold;
  font-style: italic;
}

#test8 { font-family: test8, serif; font-weight: bold; font-style: italic; color: red; }
Bloody good!
@font-face {
  font-family: test9;
  src: url(fonts/sourcesans/SourceSansPro-ExtraLight.woff);
  font-weight: 200;
}

@font-face {
  font-family: test9;
  src: url(fonts/sourcesans/SourceSansPro-ExtraLightIt.woff);
  font-weight: 200;
  font-style: oblique;
}

@font-face {
  font-family: test9;
  src: url(fonts/bogus-url);
}

@font-face {
  font-family: test9;
  src: url(fonts/sourcesans/SourceSansPro-BoldIt.woff) format("bogosity");  /* bad format hint */
  font-weight: bold;
  font-style: italic;
}

#test9 { font-family: test9, serif; font-weight: bold; font-style: italic; color: red; }
Super dooper!
@font-face {
  font-family: georgia;
  src: url(fonts/bogus-url);
}

@font-face {
  font-family: georgia;
  src: url(fonts/sourcesans/SourceSansPro-BlackIt.woff) format("bogosity");  /* bad format hint */
  font-weight: 900;
  font-style: italic;
}

#test10 { font-family: georgia, sans-serif; font-weight: 900; font-style: italic; color: red; }
Sublime!