The way they verify that you’re eligible, i.e. that you have a Visa infinite card, is by asking you to enter the first six digits of your card. Those six digits are ‘issuer identification numbers’ that say what kind of a card it is.
Great in theory, you have to know the first six digits of a Visa Infinite card to take advantage of the promotion. But that information is even available on Wikipedia, the very first result found in a Google search.
Which means that anyone can effectively take advantage of the promotion. As a Hilton Diamond member already I haven’t actually tested this out, I’m interested in it as a purely academic matter. But apparently entering the first listing in Wikipedia, for Masterbank of Russia, unlocks the page. (If I bothered looking at the code on the page I might find other ways to unlock it as well.)
Then again, they might not be trying all that hard to exclude ‘ineligible’ members considering that this past summer they gave away Hilton Gold to anyone with a Visa Signature card though that was for three months only and this is for a full year. Though in that case, existing Gold and Diamond elites got 5000 bonus points as a ‘consolation prize’ as well.
Though the benefits do vary slightly by brand and property, roughly speaking Gold status gets a (generally quite modest) upgrade, continental breakfast, free internet, and discounts on multi-night award stays.