Making a good filter for hacked pokemon is practically impossible. We would have to actually define what is a hacked pokemon. A pokemon that is created by a cheating device under "normal" circumstances is a hacked pokemon; however, how can a filter detect a pokemon that was created by Action Replay but is under the legal IVS, is under the legal EVS, is under the legal level caught, under the legal trainer that caught it if is like Jirachi for example, in the legal place caught, with the legal item caught, as you can see there are different people very clever in programming the codes, with them. As you can see its practically impossible to see this pokemon, the only factor that I could not guarantee is if there are certain hidden codes that hackers do not detect, but I think that they are very good at cracking them.