Sometimes it even more better to read over and over any terms and conditions so as to get better understanding of what is at play before one even set out to use such services.
The main problem is that some time term is not written/explained straight forward/detailed that may result in multiple interpretations. Something like "1 account per player", if we live in a big family and some of family members like to gamble in the same online casino, it should not be considered as multiple accounts unless the terms is written as "1 account per IP address". This kind of issue may also happen to anyone who like to access online casino in public places with free wifi (such as coffee shop) as the account might be connected to other accounts of other people that we never knew.