1 Photographer's right
When I sit in organising committee, I will make sure that the rights remains with the photographer. However, for the purpose of promoting the competition and its intention (like publising a catalog/book/exhibition), the organiser should have to right to use the winning and selected (accepted) photos with credits given to the photographers.
It is not right for any organisation to retain the full rights to the photos upon submitting for the competition. I personally will not take part in anyway to such competitions. I won't even take part in those that need to submit with negatives. Acceptable if only prize winning entries submit negatives. But than, it may not be an easy job for organisers to collect negative on a later date.
2) Return of prints
Well, for digital entries, how to return? Probably the organiser just keep it in a CD ROM. As for hard copy prints, after every competition is concluded, that include exhibition, notices should be send to participants to collect their prints by a certain date of 3 - 6 months. But, my experience is some ppl are very particular about collecting back their prints but some don't bother to collect. Suprisingly is those who collect are newbies and some regulars in competitions(they can submit to others). Those who don't collect are those that we see very often at the club, they keep saying later later until everyone forgotten.