I voted the Thassilon Crown down no less than six times during the post-cull phase. Any item that instantly makes a large, full-level-spread type of encounter a non-issue is a Bad Thing (tm). The idea of making all giants neutral to friendly struck me as a -very- bad idea.
Am I remembering the right item?
Yep. well, at least you remembered it :)
I did think it might be a bit much, but I thought as it's only one subtype it might be ok. Plus I didn't think neutral negated the encounter as neutral people could still attack unless I've misunderstood that, but I guess even having to explain my reasoning puts it at a big loss in a competition. I'd been playing through Rise of the Runelords with my Infernal Sorcerer and quite enjoying beating powerful enemies with my level 1 charm person spell. Nevermind. Always next year :)