With lots of money on the line you're probably not going to trust strangers with this, and the corporate bookmakers aggressively search for "duplicate" accounts

With lots of money on the line you're probably not going to trust strangers with this, and the corporate bookmakers aggressively search for "duplicate" accounts (might vary in different jurisdictions but in Australia at least you need to provide full name, date of birth, address and government issued ID to play and withdraw - you can't fake that and you'll run out of trusted family members before too long).