Of course, it's not a problem for the project owner. But with the alt of the campaign manager itself, why should you use Alt instead of the main account?
A campaign manager account that has a good reputation with a high rank, the manager can get weekly payments like other participants, even with a possibly better payment rate.
I think it would be better than infiltrating his alt account in a campaign that is managed by himself. Unless the alt account has been marked as an alt manager account, it will look more transparent.