How not, even though only one account is accepted and is in the campaign, this user wants to cheat the campaign by registering with two accounts. Don't you think it's cheating?
I've also notified the manager about the tags I gave to both accounts, now I'm waiting to see what the manager will do for them or at least one of the accounts still in the campaign. If managers don't want to hire spammers or users who break the rules, then they shouldn't hire cheaters either.
Yes, according to your evidence, he participated in bounty campaigns with multiple accounts, and that is definitely cheating. The important thing is that the cheater is detected and that the bounty manager is aware of the facts. Now it is up to the bounty manager whether he wants to keep such members in his campaign or not.
Many bounty managers decide on each participant on an individual basis, regardless of negative tags. And that's okay. Because sometimes trust scores, even from DT members, can be unfounded or unfair, so it is better for each manager to decide what works best for his campaign.
BTW, since the suspected members did not comment or try to explain their side of the story, I left a few negatives on their accounts as well.