Even if the OP did indeed have two accounts registered in this specific campaign, no rule violations occurred. Merely having an alt is no reason to get red-tagged.
I think that having two alts in the same campaign, when rules of the campaign clearly state that this is not allowed, should be red tagged.
If someone does that, he is clearly trying to cheat the campaign, this is not an honest person. So this would be a justified red tag, because trading with a dishonest person is high-risk of losing money situation.
However, as I said, this doesn't look to be the case here.