Surely you can recognise postwork , I'd have no problem helping make decision's,  surely you could implement a simple system of asking people to be truthfull with there work & add a littlecouple of letters to there work (Pw?) 
 Unfort yes it's very difficult & time consuming to moderate such a challenge , So all the best to those in charge.
 Always outspoken lol :) & has to get to work , peace!