What I've seen on the website is their policy of holder change: http://nic.do/ingles/holderchange/ It seems not so 2016 but still quite easy - by sending them the letter.
As for speculative registrations, some domains have "FOR SALE" marks even in whois records for very long time (e.g. poker.do or money.do) so it's unclear if that policy exists and how it is used in real life.