@JeremyECrawford Should players be using monster manual during game to check stars & abilities of creatures?
— fieldmechanik (@fieldmechanik) March 1, 2016
It's up to the DM whether players may look in #DnD books other than the Player's Handbook at the game table. https://t.co/jzHMaXkKng
— Jeremy Crawford (@JeremyECrawford) March 1, 2016
Let them, and change the stats on every monster…that will teach them.