We'll be adding an option to disable the inclusion in a future release. Right now, we always do it since it's a namespaced version and guarantees that things 'just work'. It should cause conflicts with your other styles, but it is one more CSS file to load.. which is always good to minimize.
To disable, you'll need to edit the /components/com_jfbconnect/libraries/provider/facebook.php file. Around line 354, you'll see:
$doc->addStyleSheet(JURI::base(true) . '/media/sourcecoast/css/sc_bootstrap.css');
Simply comment that file out or delete it and it shouldn't load anymore.
I hope that helps answer your question, and explain things a bit more.
Alex
Prevent sc_bootstrap.css from loading
