The reputation of the manager can't be a good factor to determine how trusted the project. Sometimes the good bounty managers can also get a crap project or even scam project. It's better for the newbies to keep focusing into the reputation of project.
You are right, even we can see a lot of big managers like Artezy and wapinter also holding too many project scams. A manager is an ordinary person who makes money like a bounty hunter. who pays them will be done. no matter they will scam or not.
But there are still bounty managers who like to protect their good reputation so they won't take scam projects that might only ruin them. Yes they are just ordinary people like bounty hunters but they can be a good source of courage for bounty hunters to keep going and continue making profits.