Being able to hunt/ shiny hunt specific Pokemon without encountering other Pokemon at the same time would quickly have a massive impact on the PRO economy. Rare Pokemon would become more common because of it and rare shinies would become almost worthless. The original games are mostly singleplayer (Apart from online battling) so being able to hunt rare shinies has no impact on how the games work however, because PRO is an MMO, things like shinies should be kept at a fixed rate and nothing should be able to modify that.