How can it possibly be noticed? There is no linkage required between reservations and Open-dated tickets. My AONEs use, on average about 6 different reservations during their life, and some of those never even have a ticket number associated with them in advance. There is simply no way that the airline could possibly show that you have thrown away an open-dated coupon, and certainly no way for a check-in agent to perform any lookups on the system to investigate.

Of course all this only applies if you use open-dated tickets.