jj hit the nail on the head. there are a lot more factors involved than how well your dog retrieves bumpers. try getting him involved with as many different "hunting" situations as you can before the season starts. if possible, take him to the blind/field/etc. that you'll be hunting in and let him work on getting in and out, sitting still, familiar with the surroundings, etc. personally, there weren't very many situations i would leave my dog at home in, except where he is unfamiliar or could get hurt! note: jj is very right about the problems a goose, or even some divers, can cause for a pup.
Talk 'em into givin' up!
It's easier to get forgiveness than it is permission!