Q 58

This has probably been asked to death, but what do you DM's do with Divine Metamagic in this particular regard: Persistent Spell costs a spell slot 6 levels higher than the spell you are going to persist. If the player doesn't have access yet to spell slots that high, do you let them Persist spells anyways?
Do you allow them to simply burn up the necessary Turn Attempts, or do you enforce that they must have attained high enough spell slots before being allowed to burn up the Turn Attempts?