Redundancy isn't bad in the least bit. Since computers, math and all things logical are "incomplete" (google "halting problem turing godel"). Its impossible to remove all bugs, and (this is my belief) that there is a direct correlation between complexity and the bugginess (gotta love those scientific terms). Since there will always be bugs, redundancy is used to "detect" and possibly "ignore" bugs. Critical systems, such as those used on the F-16, have numerous redundancy that are checked against each other to determine the "correct" results. Of coarse even with highly redundant systems, it is possibly that a bug will result in a uniform false result.

However, what is considered "critical" when flying faster than sound is quickly becomes "overkill" when running a perl script. In the end you have to decide just how important it is that the script absolutely runs.