What you do if pc has proficiency in dice or cards?

@matthewmercer hey matt i just read the gambling games rules and was curious what you do if pc has proficiency in dice or cards

— Drew Malland (@Aion1725) September 20, 2016

Up to you! You could allow a single reroll of a die, or the ability to add or subtract their prof mod from a roll https://t.co/KUBrrLVRxm

— Matthew Mercer (@matthewmercer) September 20, 2016