Thanks to input from this thread, I have Polaris award tickets booked for my husband and me from LAX-CHC and return next February -- all one-way, and separate PNRs. I am hoping to be able to get one of those legs at a lower fare (i.e., on miles) closer to flight time (I've got enough miles to buy that leg at the lower fare, wait til it tickets, and then cancel my higher fare ticket). But reading stories now and then about people who got downgraded from first to economy, or the like, makes me wonder: would ticketing closer to the departure date make such a downgrade more likely/possible?