For such told-you-so scenarios, when there is a disagreement and you are pretty sure you are correct, raise a ticket, describe the issue and close it "As Designed" with comment detailing the discussion (including the overruling party). Next time there is a ticket to do this with "high priority", tell them "we already have a ticket for this, let me reopen it" for everyone to see... risky though, saving face/burning bridges and all that.