growth and corisol levels. your muscles are the most insulin sensitive post workout. your body is screaming for nutrients. so u want to get that insulin spike and shuttle nutrients to the muscles with your PWO. then u really should have a real meal in an hour. it just doesnt make sense to me to hit cardio immediately unless u r trying to lose muscle mass or not maximize growth.
some prefer to do it immediately afterwards and have a different argument as to why. i just do what works best for me.
as far as they sneaking away for lunch cardio that should be fine. u might find yourself a little more tired than usual but u will soon adjust.