[its my party and]

Having come away from a competition recently I was aware that an archer next to me was shooting 3 fletched arrows and 1 bare shaft! As this was FITA competition I questioned the validity of this and was told it was quite alright. I wasn't in any position to comment not having seen a rule to the contrary but has anyone got any comments/facts relating to this "episode".
The archer in question will remain nameless but has a whole lifetime of experience where as Im inexperienced but would like some enlightenment as this didn't seem completely right in competition.