alosso: Apart from the country, the (US) state of residency may be in the mix, as some types of the game are considered differently between them, on the gambling side of it. WGT is very eager NOT to break any of these laws - always on the safe side!
Alosso, the way I read the eligibility rules (see below) are that anyone may enter the tournament as long as they are at least 18 yrs old, but that players who are outside the eligible Countries list cannot win prizes and will not move forward into the second round (Bracket Tourney)
" 2. Eligibility
Participation in the Contest is open to individuals who are 18
years of age or older. Note, however, that only individuals who are
legal residents of and physically located in the fifty United States and
the District of Columbia, Canada (excluding Quebec), the United
Kingdom, Germany, Australia, Norway, Ireland, The Netherlands, and South
Korea who are 18 years of age or older or the age of majority in the
entrant's state or province/territory ("province") of residence,
whichever is greater are eligible to win prizes. Only players who reside in countries eligible to win prizes will be entered into the bracket tournament. "