Most of the troubles an be avoided if you paying attention to the manger. You should not show hurry to join a campaign as soon as you become eligible, wait for one to be started by a reputed manager.
Famous managers are not guaranteed to get a good bounty. we still have to analyze the performance of managers.
disappointed with one of the managers and he did a great cheating.
Yes I also believe that only believing on managers will not work. Sometimes it happen that a company come to hire a well reputable manager and then they escape away cheating with the community and with the manager too. Better option is that we research ourselves about the project and we see that how the experts rate this ICO if the ICO is just alien in the community then it is a doubtful and do not spend your time for that type of ICO.
Even with the best managers, what can they do if the project decides to scam and run? I have seen one of my favorite bounty managers recently experienced their first scam after almost a year in operation, in fact 2 projects scammed them in the same day! Terrible blow to them, and of course all the bounty participants generally see whose fault it was and aren't blaming the managers, but you still get a handful of participants screaming for blood and saying that the manager owes them money for their "work".