Tricky contest holders.

Is it possible for prepaid contest holder to register as a designer and get their money  back (and all designs) by making himself a winner ?

Hey P3N, is there a specific contest that you're referring to? It's always helpful to let us know if a design entry/user account looks suspicious (i.e. new designer joins after contest launches, has an empty profile,  submits blank entry, etc.). This is partly why we ask for members to submit a screenshot to support a design entry.  Also, it's good to keep an eye out for pre-existing designs that seem to be taken from sites like GrabCAD without much modification. 

Thanks,
MacKenzie