Some of the registrars are pretty picky about their rules. I have a .es (Spanish) domain, and it wasn't until quite recently that they stopped asking you to in

Some of the registrars are pretty picky about their rules. I have a .es (Spanish) domain, and it wasn't until quite recently that they stopped asking you to include your passport number or SSN in the WHOIS entry. A number of registrars wouldn't let you buy the domain without residence in Spain either... Ended up going with a horrible registrar, and I transferred to Namecheap the moment they supported .es domains.