[SSJup81]

The only disadvantage of being an alternate, imo, is that you can't prepare in advanced like say a person who has been shortlisted. If the person has a full-time job, he or she can give a two-week notice and have more time to get stuff needed for the trip. Can't say that for an alternate who might find out as close like a week beforehand that he/she is being moved up to being shortlisted.