Usually users tend to do like this because they have paying campaign. Report it to the campaign manager so the user will get removed and get nothing, which i think he is really in a campaign or just wearing it.
As for forum rules, there's no rules for "burst-posting", unless the posts are considered and reported as spam. But if the posts are somewhat good, then there's no issue at all.
I certainly agree. Report to the campaign manager instead so that he will be automatically warned and if there’s no improvement after that, then the campaign manager will be responsible enough to remove the poster or ban his account in all of his campaigns.