It’s been around awhile and is offered to the higher end suites if they are linked to your reservation, but it’s not always offered. Depends on how many retreat guests are booked for each cruise. It cost around $100 per day, per guest and I believe it has to be purchased for the entire cruise, you can’t buy just a day or two. It does not give the guests the perks of booking a suite (drink package, wifi etc) It just allows them access to the retreat lounge, deck and Luminae. If your parents are looking to book a suite lower than a Royal Suite, they won’t get the offer. The only other option would be dining in Luminae with them, at a fee per meal, per person and it needs to be arranged prior with the Maitre d’ as it’s on an availability basis.