[AJ007]

The example the author gives is of poorly executed form validation. His solution is to to tear down the firehouse because a firetruck hit a single pedestrian -- "Always try to avoid input validation wherever it is possible and not required."

If you have received a large sample from, say, 1,000,000 users a certain % of those entries will be invalid. The number of users is too large to manually fix or attempt to contact the user to fix the entry. If the contact information is invalid, you can not contact the user. If the contact information is invalid but you think you may be able to correct it, e.g., add a .com to the end of "user@gmail", you may not even legally have permission to contact that person.

The goal is to reduce the invalid % to as low as possible. There is no 100% perfect rate. You are going to sacrifice 1 user for 10.