For me, as for a bounty hunter, this is a good idea, since I will be sure that I will receive my guaranteed reward and my efforts are not in vain! But for the ICO itself such a move is not very good ...
I think that they pay a reward in the tokens of their project in order to popularize it at the expense of us, so that there will be more users, more volumes on exchanges - something like that. It is necessary to seek a compromise on this issue between the bounty hunters and the project team.