I know this subject has been discussed a couple of years ago but I think AP members might benefit from a re-visit.

Kings Park in Perth are having a festival, including a photo competition called "Wildflowers in Focus".

See: http://www.bgpa.wa.gov.au/festival/competitions

I was very tempted to enter, considering it has a nice 3 night holiday prize, until I read through the terms and conditions. Here are some relevant parts to those:

You agree not to use, or permit the use of, any images taken of or from Kings Park and Botanic Garden sites for any commercial or promotional purpose other than entering this competition or your own personal use.

You expressly agree not to use such images for commercial purposes such as sale or license to third parties.

On completion of this competition, all photographs received as entries will become the property of The Botanic Gardens and Parks Authority. The Botanic Gardens and Parks Authority has the right to use images for the promotion of Kings Park. The photographer will be appropriately credited if/when their image is used.

The winner agrees to grant the Promoter a perpetual and exclusive license to use the photographs in all media worldwide and the winner will not be entitled to any fee for such use. The winner agrees they will not, and will ensure that their companions do not, sell or otherwise provide their story and/or photographs to any media or other organisation who are not associated with this promotion.
I may be wrong but what I read into this is that as soon as I enter my photos I give up any right to using them ever for commercial purposes, and I won't get anything for them if they are used by Kings Park for any reason (unless I happen to win the competition).