I am not sure about policy, but I personally could not go off and leave something cooking in an area such as a hotel where other people are.
If, heaven forbid, something did happen and catch fire, it would just be horrible.
I double check every day we leave the room to make sure no irons, curling irons, or anything is left on.
I know the chances are minuscule but I could not have a good time knowing I had left something cooking in a hotel.