Sigh. My first sentence was a direct response to your silly question: "Spencer's idol could not be played after the votes came out. Are you thinking of Tony's superidol?"… from there I clarified the strategy.

You need to read better:

How is this difficult to understand for you? During tribal council, while Jeff is interviewing everyone, Jeremiah shows that he has an idol. The others immediately start whispering to each other "spencer'. Spencer gets all the votes as Jeremiah returns the idol to him and NONE of them count. Then Jeremiah, Spencer,…

Well, you play the idol after the vote when Jeff asks if anyone wants to play an idol. If Jeremiah had simply flashed it, the other alliance would've switched the vote to Spencer. Then everyone votes, and Jeremiah gives it back to Spencer. Spencer plays it, saves himself and one of the other alliance is going home…

I was screaming at the TV. An easy tactical decision for Spencer,
would've been for him to slip the idol to Jeremiah pre-tribal last week! The arrangement would be, after the votes actually came out Jeremiah would give it back to Spencer to play. Jeremiah presenting the idol pre-votes at tribal would've made the…