You can’t choose not to use that knowledge. You can choose to act in a way other than the way that knowledge would otherwise lead you to act, which is itself using that knowledge. So, again, what you’re actually describing as metagaming is not using OOC knowledge but taking actions that OOC knowledge would lead you to take.
I was just pointing out the standard definition of metagaming. Nobody I know would accuse a person with OOC that doesn't use it to be metagaming.
