I was on a WN flight several months ago with my wife. My wife is the one that actually pointed this out to me. An off duty WN FA was sitting in the aisle seat and one foot (she had shoes on) was resting in the seat back pocket and the other one was resting on the tail end of the armrest of the seat in front of her. The unusual position resulted in a direct view of her panties (she had short WN uniform shorts on).

So I guess you can put your feet in the pockets as long as you have shoes on???