>>39701382>How is it different from catching them with pokeballs and selling them for profit later?Pokemon that are caught with balls are permanently tagged with the original trainer ID, even if they're released (source: N's pokemon in BW2), which could incriminate anyone who buys one from poachers if the operation gets busted or leaked. For example, if Pokemon Centers scan IDs then they could be set to automatically alert the police if someone brings in a pokemon that has the same trainer ID as the poachers.
A poached pokemon that's kept in a cage still technically counts as wild, so whoever buys it will be registered as its original trainer and be nearly impossible detect.