Well unlimited would be impossible, but there should be no restrictions on how much one could gamble. I know for sure that this limit is hardcoded in the addon itself and that this is not something that has been added by any of you guys but I have checked it earlier and it is pretty simple to change the limit if you know what you're doing. As an active chess player on the server this is a game changer for me and adds even more risk and fun to my games.
