There is nothing wrong to be a Co-onwer of Roobet but i don't know it does create some confusion in the mind, maybe because the site is new one. However i think if your signature campaign manager endorsed this, then all the confusion will be removed as he is trusted person here.
If roobet.com will scam customers, will the signature manager compensate the damages?
Why would he ? Signature campaign manager is responsible for the campaign and payments to those who participate in the campaign. If any issue in payment of campaign, only then you can held the campaign manager responsible.
Becoming a campaign manager, does not mean that he has become the owner of the business. He is only doing a Job.