The system works. Here are 2 situations where it doesn't:

1/ say for example you have a file with 10,000 rows. If there is a single character in that entire file that the checker doesn't like the entire output will be corrupt. They know this and have no intention of fixing it. Its probably a very simple fix. Too bad.

2/ If you want to clean a list that has more than just email the its not practical. See point 1.

Its too bad they can't include some basic error detection and simply remove or ignore the offending record.