You're given the choice of how you'd like SELinux set up: off, warn on potentially unsafe activity, or deny unsafe activity. The 'warn' option, IIRC, is the default; if you choose to have it outright deny stuff, the installer tells you up-front that this is likely to prevent certain programs from working and that if you encounter problems you should turn off SELinux.

\r\n\r\n

Looking at screenshots of the install, it looks like this only comes up when you do a custom installation. Which, really, is the only sane way to install Fedora.