I hope they won't do it. I really hate it when I open a game and it turns out it has music/sound effects turned on by default. I don't know why they always choose high pitched sounds which hurts the ears!
Having a default sound is good but it should be not over loud and too noisy. If people want to have bigger sound, they can turn their volume up. I think a default volume should be soft enough and it is at 50% of max volume or lower than 50% of max volume if the team want their max volume is very loud.
If Neodice can allow users to have different sound tracks to choose when they are betting, it is more user friendly.
Music/sound effects or anything else that may cause inconvenience even for a small pourcentage of players should be turned off by default. Others, who like it, can turn it on whenever they want. This way all players will be satisfied and you won't enforce your preference on others who might not like it.
It increases adrenaline for gamblers and make them more engaged in the game, though it can bring inconvenience to gamblers who don't want to be distracted by noise. It is important for gamblers who do multi tasks at the same time, trading, gambling, listening to music perhaps.