In my opinion, this is not such a big problem, because I can distribute the participants for all other projects! After all, in large projects, thousands of participants come, and in smaller projects only dozens of participants! But the quality of the project and its growth depends on advertising!
It was okay even there are many participant, in fact it will be a big help for their project to become more successful. The manager know that he can manage it and I think he will just have limit if he cant manage too many particapant, but most of the bounty campaigns are limitless. Only depends on the ranks of every participant that they are accepting.