Apple has the opposite problem. On my version of OSX, Spotlight searches in the Finder return email results too, which increases the noise-to-signal results dramatically. You can turn it off but this requires you to enter your search term as a formula every time--there's no way to make it the default. If I want to search my email, I'll switch to the Mail program and search there. I neither want nor need to search my mail in the Finder.