Actually thats not entirely true Rick. Regardless of the commercial use, most competition terms and conditions, as a standard, include some provision for a statement or a requirement that states that the entrant has the permissions required to cover their entry.
Most competitions actually insist on a model release - regardless of the issue of "commercial use" etc. If organisers dont have a model release, while they may not in the technical sense need one, they may still be putting themselves at risk of at the very least a takedown notice.
So even the very best competitions (and I check a great number of them) put a standard rule in about model release or permission - for instance
"# You confirm that each person depicted in the Entry has granted permission to be portrayed as shown."
And
"Each entry must not infringe upon the copyrights, trademarks, contract rights, or any other intellectual property rights of any third person or entity, or violate any person's rights of privacy or publicity."
And this is from a good competition.
Its worth noting that competitions produce their own terms and conditions a bit like the way any other business chooses the terms they choose to do their business. So, while terms and conditions cannot ignore state and federal law in Australia - they can certainly be more careful then the actual law or laws offer individuals. Why ? Because as I continue to say, there is no Black and White in Law - its interprative. And its also worth noting that most competitions produce Terms and Conditions that are produced by legal specialists, that are very experienced in the associating areas of law.
The most important clause in a Competition Terms and Conditions, is the "organiser get out clause", which puts the legal and possible resulting financial costs back to the entrant, in the case of the competition organiser being sued for someone's image being used, when they had not signed any waiver/release or provided permission - and this is again a typical one direct from (again a good) competition:
"You agree to fully indemnify ________________ in respect of all royalties, fees and any other monies owing to any person by reason of Your breaching any of the foregoing."
So I wouldnt be too quick to feel safe by assuming that somewhere as unassuming as AP would be safe because there is no money being made out of the use of the photo. I dont mean to sound alarmist, but the clause stipulating that you have permission to upload images - even to Flikr, Facebook etc, you are agreeing that you have permission to upload that image. If you dont, then you are breaching that site's rules and you will be held responsible.
My advice for competitions is read the rules - read them well. And if you think its easier at the time t get someone's permission, or acquire a signed release, please trust me that its much easier to do it then, as opposed to a month, a year, or years down the track, when you want to enter an image into a competition, or post it on your own website, or someone elses.