They are basically two other credit reporting agencies...apart from the regular three.
The Club Carlson card sometimes pulls these reports, and people find themselves getting denied because of some discrepancy in their ARS or IDA report.
The complete instructions on how to go about freezing your reports is available here:
http://hackmytrip.com/2013/06/freeze...-club-carlson/
His site is down right now, but give it a look once it's back up.