It's very strange that you and your wife are having different experiences with the same belt, FireBrick. The only thing I can think of is noted on page 20 of the 2009 Element owner's manual:
The seat belts in all positions except the driver's have a lockable retractor that must be activated to secure a child seat (see page 46). If the shoulder part of the belt is pulled all the way out, the lockable retractor will activate. The belt will retract, but it will not allow the passenger to move freely. To deactivate the lockable retractor, unlatch the buckle and let the seat belt fully retract. To refasten the seat belt, pull it out only as far as needed.
Is it possible your wife is pulling the belt all the way out before buckling it?
The seat belts in all positions except the driver's have a lockable retractor that must be activated to secure a child seat (see page 46). If the shoulder part of the belt is pulled all the way out, the lockable retractor will activate. The belt will retract, but it will not allow the passenger to move freely. To deactivate the lockable retractor, unlatch the buckle and let the seat belt fully retract. To refasten the seat belt, pull it out only as far as needed.
Is it possible your wife is pulling the belt all the way out before buckling it?