Almost every team has done that though. For whatever reason we seem to consistently play a bend but don't break style of defense. As long as the opponent isn't in scoring position we're completely content giving up 4-8 yards with every pass until they are in FG range at which point we attempt to actually stop them from progressing further with mixed success.

It really feels to me that the defensive game plan is to be willing to concede yards/points early in order to 'trick' the other team into using a specific strategy that our formations are obviously vulnerable to. Then once the other team has committed to that strategy we activate our trap card and suddenly shut those plays down and hope the sudden confusion throws them off balance for the rest of the game.