@Sparks Choose your poison. You're either keeping the great RP behind a wall where no one can see OR you're risking spoilers and metagaming.
Personally, I think the answer may be to create a spoiler tag for log entries and then double down on keeping an eye out for metagaming.
For example: Log32222 shows that CHARBIT found a secret temple hidden underneath a path of hills that no one would really bother to go to unless they had a treasure map, which CHARBIT did. They entered the hidden temple by pushing on one particular rock on a hillside.
CHARBIT2 suddenly just la-Dee-dahs out to said random hillside and decides to practice hitting a baseball bat against every rock on that particular hillside because it would be totally on accident that they'd hit the right one and oops their way into a hiddle temple they knew about OOCly.
It's a risk, but enforcing good/fair RP would protect against it.