In regard to the "hidden fee" aspect of the "gratuity" fairy tale here's what I wrote in a previous post:
When it comes to advertising bogus/teaser cruise prices Viking is no better than the rest of the pack - and they should be. As in the case of "resort fees", "convenience fees", "processing fees", etc., etc., etc., if you can't purchase the product for the price advertised the advertised price is a fraud. Viking is not upfront about what it calls gratuities, the average customer finds out about them in "Oh, by the way" fashion. They even get away with the "prepaid gratuities" nonsense.