The only solution to bounty scam is escrowed and this is only what good bounty platforms or bounty managers should introduce to at least limit disappointments of not getting paid
Not only escrowed but also ther developers should also pay bounty hunters with trade able coin or tokens I love to see the day that we are going to get paid with trade able coins so they cannot stop blaming bounty hunters of dumping their token, developers are so quick to blame bounty hunters when there's dump.