Lion 10.7.3 bug affects shell script executables

After suddenly running into bad interpreter: Operation not permitted errors trying to run a shell script, I uncovered the following on the Apple Support Communities forums

...there appears to be a bug in the latest version of OS X Lion in which the quarantine flag is attached to existing files on the system, preventing some code such as user scripts from being executed. If you create shell scripts, for instance, then opening them in TextEdit and making changes to them will result in them no longer being executable and will result in an "Operation not permitted" error in the Terminal.

That was exactly what I had done, I opened a shell script with TextEdit just to copy part of it to send in an email.

If you run into this problem, see this link for the fix.