If you are redeeming for yourself I don't see why but I am curious why you think so. I mean if there is an account registered in the name of John Smith and then four years later John Smith books a flight for himself why is that suspicious? Now sure if a four year old account in the name of John Smith decides to book a flight for four other people none of whom have an obvious connection to John Smith and he isn't on the booking then yeah very suspicious (potentially a compromised account).