Unless the bitcointalk staff makes Escrow for bounty hunting compulsory and the bounty manager did not comply. That is when we can admit that the bounty manager has breaking the rule and can be red tagged. Since nothing like this exist, there is nothing anyone can do to them. Many of them do write disclaimer post at the bottom of a bounty post, stating that they are not part of the team
There are no rules for conducting a bounty campaign on the forum, including one that provides for escrow. However, escrow is common in signature campaigns where payment is made in BTC. If escrow is not provided for by bounty, then each bounty hunter must independently conduct research on the campaign they want to join. In addition, they should pay attention to whether the Manager has experience in conducting bounties and how successful they were in the past.