I have the perfect solution to the whole argument of copyright etc.

In the UK we have a policy where all coursework material you submit to the exam boards has to have a reference section at the end, where you put links to all of the places you have sourced your material from.

It works well to combat plageurism

Maybe in future competitions make it compulsory to list the sources where you got the material from, because if all of the entries submitted are owned entirely by the submitter, it looks like half of the population of the forums are accomplished graphic designers :')