Prior to the uncapped year, the NFL competition committee warned teams that punishment would be levied for taking advantage of the circumstances. What they didn't want to see happen in an uncapped year was to have teams spending massive amounts of money on free agents, taking advantage. The Redskins and Cowboys were the most egregious offenders, as they dumped huge base salaries to players such as DeAngelo Hall, Albert Haynesworth and Miles Austin into the 2010 season in order to get the big numbers in those deals off the books while there was no cap.
Now, they'll pay, as the NFL has decided to penalize them by reducing cap space and spreading that extra money to the other teams that complied with the warning.