Restrictions on winnings can be very different or not exist at all. In some countries, profit restrictions are imposed by justice. In such case, everything is written on the casino website. But in most cases, they just don't exist. As such, withdrawal limits may exist and are sometimes very strict. There are examples when an online casino no deposit bonus only allows withdrawals of C$5000 per week. For a beginner, it's a huge sum, but for a professional player, it's a significant disadvantage. All limitations are related to legislation or safety rules.