[Boaz]

Midnight, that's some interesting thinking there...

I think it's strange that Olenna and Marg would use moon tea to force the issue because moon tea would immediately call Marg's fidelity into question.

Mayhaps Marg and Olenna are trying to get Marg pregnant and claim the child as Tommen's. If Marg had a son, then the Tyrells could kill Tommen and move themselves into power equal to, if not greater than, the Lannisters. Remember, the Lannisters are trying the exact same ploy with Edmure Tully and mayhaps Robb Stark.

I don't know what the moon tea is for. Mayhaps Marg tried to employ Olenna's plan, but stupidly slept with a Kettleblack or some other black haired man. Any son of Marg must have brown hair or lighter to be considered as Tommen's... unless the Tyrells try and claim a recessive Baratheon gene.

Mayhaps Olenna's insistence upon the one night was to get it into Tommen's head that spending the night with Margaery is a good thing. If he makes a habit of it, then Marg will be ready when Tom's balls drop.

Mayhaps the whole thing is to make the Tyrells seem trustworthy and to lull the Lannisters into complacence.