It's really a toss up.....sometimes they are in resort rooms and sometimes you just have to check the DIS for information before you leave and call the number and give them the code. We have had the bounceback in our rooms most years (Value resorts) but sometimes I guess the housekeepers don't have any flyers left so they don't put one in your room?
In that case the DIS comes in handy....usually someone will post a picture of the flyer and it has a code and you can just call reservations from your resort room and give them that code and they'll let you book