well in theory if the rpmfusion drivers modules for the new kernel are not there yet, or pushed to your mirror, the yum update should fail with dependency errors.
"$ su - bofh"
OS: Mac OSX Snow Leopard (x64 by default), W7_Enterprise_X64, F12_x64_KDE
Hardware: late 2009 Macbook 13", MSI Wind 10"
Browser: Opera 10.10, Safari 4
Registered linux user #459910