Well, RCT isn't the only title that removed SafeDisc in later patches.
It turns out the Infogrames 2001 reissue of Risk II that I recently acquired is just a simple CD check title as well, with no SafeDisc anywhere. You may need to check to see if any reissues of Hasbro-era MicroProse titles utilize the DRM or not because I don't own many (And as I live in the UK, I wouldn't know if later re-releases in the States would use SafeDisc or not).